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XUM 


Octoser 1, 1895.] 


KNOWLEDGE. 217 














ILLUSTRATED 


aie OF SCIENCE 
SIMPLY WORDED—EXACTLY DESCRIBED 




















LONDON : OCTOBER 1, 1895. 





CONTENTS. 
— > PAGE 
Everyday Botany. By W. Borrina Hemstey ... 217 
The Field-Naturalist and the Camera. The Kenenel 
Hawk, By Harry F. Wirnersy. (Illustrated) we 28 


The International Geographical Congress in London. 


(Continued from page 196) 219 
Lightning Photographs. (Illustrated) ve S24 
Coal Mine Explosions and Coal Mine Fires: their 

Occurrence and vienateiaaaiell By D. A. Lovts. 

(Illustrated) are : see . 224 


Science Notes ... : ne bas a w. ©6227 


Notices of Books. (Illustr sina aa w. 228 
The Visibility of Change in the Maen: By H. G. 
WELLS, B.Sc. ... : 230 
The Size of the Solar duetem. By J. E. Gene FRAS. 231 
Photographs of the Cluster Messier 13 Herculis. 
By Isaac Roserts, D.Sc., F.R.S. , es 232 
Letters :—T. W. BackHovsseE; pon henna: C. Fr. 
MarsHatt, M.D. ; Aurrep J. JOHNSON ; WALrer 
WESCHE. (Illustrated) 233 
The Voyage of H.M.S. “ Challenger” one its Aanteve- 
ments. By H. N. Dickson, F.R.G.S._... 235 
The Face of the Sky for October, ™ — 
Sapter, F.R.A.S. eas 238 


Chess Column, ent Cc. D. Lesncn, B.A.Oxon. 29 





EVERYDAY BOTANY. 
By W. Bortine Hemstey. 


OTANICAL teaching and botanical knowledge have, 
doubtless, considerably advanced in this country 
during the last twenty years; but it is doubtful 
whether the right kind of knowledge is being 
taught to children and young persons who have 

no prospect of obtaining an advanced education. Many 
travellers assert that savage and semi-civilized races 
possess a more useful and a more general knowledge of 
the plants of their respective countries than our own 
people do of British plants ; and Mr. H. O. Forbes goes so 
far as to state that the Sundanese, a race inhabiting Java, 
had a name for and could tell the history of every tree 
and plant and minute shrub of their country. “In this 
respect,’’ he says, ‘‘ the Sundanese excel far and away the 
rural population of our own country, among whom, with- 
out exaggeration, scarcely one man in a hundred is able to 
name one tree from another, or describe the colour of its 
flowers or fruit, far less to name a tree from a portion 
indiscriminately given to him.” As examples of their 
botanical knowledge, he states that they group the laurels 
and oaks each under a generic name, and of the former 
they distinguish by name no fewer than sixty-three species, 
and of the latter sixteen. 


= | 


|| 








Whether Mr. Forbes had to do with Sundanese of 
exceptional knowledge of natural history, we cannot say, 
but it is to be feared that his estimate of the acquirements 
of his own countrymen is only too true, in spite of the 
thousands of candidates that present themselves annually 
for examination in this subject by the Science and Art 
Department. 

Unfortunately, the simple, practical, and useful are often 
lost sight of in elementary teaching and examining, and 
technicalities and theories are taught before the pupil is 
able to distinguish the commonest plants. This should 
not be understood as decrying the study of botany from a 
more philosophical standpoint than was formerly the case; 
but considering the importance of the subject in everyday 
life, it is surely more desirable that persons having little 
time for botany should learn domestic or economic botany, 
rather than a smattering of vegetable anatomy and physio- 
logy, or the life-history by rote of some microscopical 
organism, which they probably may never see. Our food 
and drink, our clothing, furniture and dwellings, our 
gardens, fields, woods, and mountain-sides, are all so many 


| books full of botanical facts, that it is both useful and 


intellectual to know, even if only superficially. To be able to 
tell an apple tree from a pear tree, an ash from a walnut, or 
a beech from a birch; to be able to distinguish cotton from 
linen, and say what part of the plant yields each respec- 
tively ; to know that tea is the leaf of a kind of camellia, 
that coffee is the seed of a tree of the same family as the 
gardenia, that chicory is the root of a plant closely allied 
to the dandelion and lettuce, that mustard is the seed of a 
plant hardly distinguishable from the turnip, that white 
and black pepper are berries of the same plant, the former 
with the outer skin removed; that ginger is a root, that 
cork is the bark of an oak tree, that quinine is obtained 
from the bark of trees of the same family as the coffee, 
that sugar is extracted from beet-root as well as from 
the giant grass called sugar-cane—such is the kind of 
elementary botany that should be taught, because it 
is all useful knowledge, and its acquirement is a good 
preparation of the mind to receive more, and a good 
foundation on which to build. It may be urged by 
some persons that this is not botanical knowledge, but 
this is a point that does not call for discussion. For the 
same utilitarian reasons, children, or adults for that 
matter, should be taught to discriminate between horse- 
radish and aconite-roots, parsley from the similar and 
often poisonous members of the same family, the mush- 
room, and other common edible fungi, from such as are 
deleterious, and that no fungus should be eaten except in 
a young and fresh state. Following such knowledge, or 
concurrently with its acquirement, practical demonstrations 
are recommended of the natural orders and important or 
exceedingly common genera from fresh specimens ; always 
fresh specimens, and, by preference, the commonest 
plants, beginning with such as have large, or tolerably 
large, flowers. Having got thus far, the pupil might 
then be instructed in the general principles of growth 
and nutrition of plants, especially such facts as are 
demonstrable or easily understood, following with the life- 
history of some common and easily observed flowering 
plants. Of course, it should be borne in mind that 
elementary botany only is under discussion ; but however 
deeply the student may eventually dip into the microscopic 
mysteries of plant life, he should first of all undergo a 
training in distinguishing objects by sight, and in tracing 
the origin of vegetable products. 

Allusion has been made to the desirability of a know- 
ledge of the properties of plants, especially of common 
wild plants. Teaching in this branch of the subject should 





218 KNOWLEDGE. 


[Octoser 1, 1895. 





embrace roots, leaves, and fruits. Ignorance on this 
point has often led to fatal results. Livery season has its 
victims, who are chiefly town-bred ; for country children, 
who eat a great variety of vegetable products, from pig-nats 
to hips and haws, to say nothing of the more luscious berries 
of various kinds, are early taught by tradition that certain 
plants are poisonous. 

Another branch of botany requiring little mental effort to 
master its general principles, is the geographical distribution 
of plants. Taking the British flora, for example, as a basis, 
it is something to know that it does not contain a single 
peculiar species of flowering plants—at least no very 
decidedly distinct species—-and that it forms part of a flora 
that stretches from the Atlantic eastward to the Pacific, 
and, in a less pronounced degree, all around the northern 
hemisphere ; that it also has the widest latitudinal 
extension of any flora, remains of it occurring on the 
mountain ranges of America, Africa, and Asia, southward 
to Cape Horn, the mountains of tropical Africa, and 
Australia and New Zealand; that the common ‘ ladies’ 
mantle’’ is found on the Australian Alps, and that a 
primrose abundant in the extreme south of America is 
hardly distinguishable from Primula farinosa of the north 


of England ; and, finally, that there is a greater variety of 


beech trees in South America, New Zealand, and south- 
eastern Australia than in the northern hemisphere. A 
person whose knowledge of botany is of the kind indicated 
in the foregoing remarks is in a better position than the 
‘* pot and pan ”’ botanist whose education does not include 
these commonplace facts. The examiners in botany of the 
Science and Art Department have recognized the impor- 
tance of knowing these small things by setting a question 
this year on culinary botany, in which the candidate is 
asked to state what part of the plant is eaten of a number 
of different vegetables. 





THE FIELD-NATURALIST AND THE CAMERA. 
THE KESTREL HAWK. 


By Harry I’, Wrrnersy. 


HE usefulness of photography as an aid to science 
is not yet, perhaps, thoroughly appreciated, nor 
have its applications been exhausted. We have 
long known it to be of the greatest possible help 
in astronomy, microscopy, and other sciences, but 

as an aid to the study of birds and animals, photography 
is still in its infancy. We feel sure that when properly 
taken up by field-naturalists, it will be found to be an 
exceedingly valuable adjunct to the gun and field-glass. 

Several reproductions of photographs taken from life, of 
birds and animals, have already appeared in KnowLepce 
during the last two years, and this month an enlarged 
reproduction of a photograph of some young kestrel hawks 
in their nest is put before the reader. 

About four o’clock one bright, sunny morning in June, 
when taking a stroll in a beautiful park in Ireland, I met 
one of the keepers of the place, who offered to show me a 
kestrel’s nest. Arriving at the fir tree in which the 
kestrels were, I began at once to climb, and had 
gone some distance up the trunk before the hen bird 
flew off, so closely did she sit. In one of the boughs 
near the top of the tree, about forty feet from the 
ground, there was a dense growth of twigs about a 
foot high, and on a platform in the midst was what at 
first sight looked like a mass of yellowish down. This 
proved to be six young kestrels, so mixed up together, and 
so plentifully plumaged, that it was difficult to count them 





or to say which hooked beak or curved claw belonged to 
which ball of down. When touched they began to cry 
plaintively, and this brought an answering note of alarm— 
a sharp kee, kee, kee—from the hen bird which was flying 
about not far away. 

The unique position of the nest, and the beautiful stage 
of plumage in which the young birds were, suggested the 
idea of photographing them. The advantages of the 


position were many—the tree was a fairly isolated one and 
well exposed to the light ; the nest, being a mere platform 
of twigs, was not deep enough to hide its contents, while 
the branches over it were not thick enough to obscure 


Young Kestrels and Nest in Fir Tree. 


the needed light, and the tree was easy to climb. 
This last fact enabled me to go up to the nest at 
various times of the day to select the best light, and 
accordingly at about eleven o’clock the next morning I 
climbed up the tree with hand-camera, rope, and saw. 
First some boughs had to be cut off to let in more light 
upon the nest, and others had to be tied back for the same 
reason. It was impossible to take the photograph from 
the side nearest the trunk, owing to the thick growth of 
twigs. On the further side, the bough, which was in no 
place very thick, divided off into three branches. Here 
the usefulness of the rope came in, for passing it round 
the trunk of the tree and myself, the thin boughs were 
freed of a good deal of weight, and 1 was enabled to use 
both hands to the camera. When the latter was brought 
to bear on the birds a great many twigs were found to be 
in the way, so the camera had to be balanced on a branch, 
the rope unlashed, and the saw brought into use again. 
At last when everything was ready the sunlight disap- 
peared! After I had waited a quarter of an hour in a very 
cramped position, the sun shone again, the birds were 
tickled with a twig into a good attitude, and eight or ten 
plates were exposed. Not feeling quite sure that the 
camera was far enough away from the subject to be in 
focus, I measured the distance and found it to be a foot 
too near for the focus of the lens. So all the photo- 
graphs taken, as was afterwards proved in developing, 
were useless. It was not easy to get back another foot, 
and retreating cautiously, I found that my weight bent 
the boughs down so far that the camera could not be 
held high enough to take in the picture. A happy idea 
then occurred to me. I regained my former position 











Enlarged JSrom a hotograph taken from life. 





Knowle lqe. 


NEST OF YOUNG KESTREL HAWKS. 


Enlarged from a photograph taken from 1 














XUM 








Ocroser 1, 1895. | 


KNOWLEDGE. 


219 








and turning round sat back to the birds, holding the 
camera in one hand in front of me and pointing it over 
my shoulder. Thus the right distance and elevation 
were obtained, and the result may be seen in the two 
accompanying illustrations. It will be noticed that the 
birds are very much huddled up and sleepy-looking in 
both photographs, but having my back to them it was 
impossible to keep them in good attitudes. In the small 
illustration the bough from which the growth sprang may 
be traced back to the trunk, and the general position of 
the growth itself is better seen than in the large one. 

A great deal of time and a certain amount of patience 
are undoubtedly needed in photographing birds and beasts 
from life. There are sure to be many disappointments, 
even after an immense amount of trouble has been taken. 
Nevertheless, let me urge upon field-naturalists the im- 
portance of taking up photography as not only a pleasure, 
but an extremely useful adjunct in their pursuit. 

To pass on from photograph to subject, it may be said 
that the kestrel hawk,* which is a tolerably common bird 
in the British Isles, will no doubt increase in numbers 
now that farmers and gamekeepers are beginning to under- 
stand its usefulness. Just as there are ‘“ rogue ’’ elephants, 
so there are ‘‘rogue” kestrels. These will go into the 
pheasant field and take the young chicks. But it has 
been well said, ‘‘ Never shoot a kestrel unless you see 
it in the act of doing damage.”’ 

he usual food of the kestrel is composed of rats, mice, 
small birds, beetles and other insects, and of the first two 
it destroys great numbers. Its graceful movements in 
the air when in search of food demand admiration from 
everyone. Hovering over a field, suspended as it were in 
space, it seems fixed and motionless but for the rapid 
beats of the wings. This feat, which has won for it the 
name of ‘ windhover,”’ is by no means an ordinary one. 
Few birds, and no other British hawk, can accomplish it, 
and the kestrel itself would be unable to hover, did it not 
make use of the wind, however little there may be stirring. 
When in the act of hovering, it invariably has its head to 
the breeze; and its body is placed at such an angle, 
according to the strength of the wind, that the bird is 
stationary in space. The forces of the wind and 
wings meet and balance each other, while both help 
in counteracting gravity. It will be noticed that on a 
very windy day the kestrel’s position when hovering is 
almost parallel to the ground, while on a very still one it 
is almost vertical. From its elevated position it takes in 
the surrounding land at a glance, and the smallest mouse 
in the grass beneath will not escape its keen sight. With 
a downward swoop it drops on its prey like a stone, and 
transfixes it with its sharp talons before escape is possible. 
One of the most striking sights in bird life I have ever seen 
was the action of three kestrels as they hunted a mouse- 
infested wheat stack. They hovered above it with the 
sides well in view, and every time a mouse incautiously 
appeared at the edge, one of the birds dropped down upon 
it, and, clinging to the side for a moment, flew off again to 
devour the captive in a neighbouring clump of trees, from 
which it soon returned to renew the hunt. 

The kestrel very rarely builds its own nest. A hole or 
a ledge in a cliff or quarry is a favourite site in many 
districts. In woods it uses a hole in a tree or an old or 
deserted nest of a crow, magpie, or some such bird, in 
which to lay its eggs. These are five or six in number, 
thickly speckled with rich brown. The young are at first 
covered with down, and when in this condition they are 
harmless. Nevertheless, they place themselves in all sorts 


* Faleo tinnunculus. 





of defensive attitudes. To lie on their backs with open 
mouths, and tear at the intruder with their claws is a 
favourite position, while at other times they stand up in 
the nest, and, flapping their wings, strike with the beak. 

At all times and at every age the kestrel hawk is an 
extremely interesting bird, and in captivity it forms a 
most pleasing pet. 





THE INTERNATIONAL GEOGRAPHICAL 
CONGRESS IN LONDON. 


(Continued from page 196.) 
OCEANOGRAPHY, 


HIS subject was opened by Mr. J. Y. Buchanan, 
F.R.S., who, after referring to the London 
Congress as coinciding with the completion of 
the Challenger Report, proposed to look back 
to the state of the oceanography before, during, 

and since the great expedition, and at the direction which 
investigations should take later on. On the first line of 
soundings across the North Atlantic the Chullenger 
found the calcareous deposits limited by depth, and 
discovered the abysmal ochreous and argillaceous deposits, 
and peroxide of manganese was found in all of the earliest 
dredgings. The limitation by depth of the calcareous 
deposits suggested to Sir Wyville Thomson his solution 
theory. The areometric method of ascertaining salinity 
was approved, and the instruments used in expeditions, 
from the time of the Challenger to the present, were 
particularly described, and the possibilities in the improve- 
ment of oceanographical instruments were adverted to. 

The Prince of Monaco contributed a paper detailing the 
recent work of his yacht the Princesse Alice, which 
had been built and fitted specially for oceanographical 
investigation. Soundings are made by a cable of three 
strands, each of three very fine steel wires, the whole 
only one-tenth of an inch in diameter, and very flexible. 
Very important zoological discoveries were made by a 
deep-sea trap of wood and network, on the principle of the 
lobster-pot, for many of the animals obtained by it could 
not have been procured by the ordinary trawl or dredge. 
It is suspended by thirty fathoms of rope, connected by a 
swivel with a steel wire cable of four thousand fathoms, 
in lengths of two hundred and fifty fathoms, easily 
separated at any joining. This apparatus showed that 
the deepest waters of the western Mediterranean swarmed 
with highly organized life, and valuable biological results 
were obtained in the Bay of Biscay at a depth of two 
thousand seven hundred fathoms, while a fish, Macurus, 
two feet six inches long, and some remarkable holothurians 
had been brought from a depth of two thousand fathoms. 
A submerged electric light for attracting specimens had 
also been used with success. 

A paper by Captain A. S. Thomson, R.N.R., classified 
the movements of ocean water as stream currents, flowing 
at the surface and occasionally extending to a considerable 
depth ; counter currents, which return the excess of water 
conveyed away by the induction of the stream currents ; 
drift currents, due to winds blowing continuously more or 
less in the same direction; and periodic and sub-surface 
currents. Sub-surface currents form an important factor 
in oceanic circulation, and offer a rich field for scientific 
discovery. Evaporation is the chief cause of oceanic 
circulation. In the trade-wind regions, from each square 
inch of surface in twenty-four hours, a cubic inch of water 
evaporates, and the current chart of the world shows that 
the principal surface currents circulate round the areas 








220 KNOWLEDGE 


[Octoser 1, 1895. 








GP SERA a 





where evaporation is greatest. The westerly equatorial 
flow is not directly due to the impelling force of the trade- 
winds, for if all friction between the sea-surface and the 
trade-winds were removed, the general oceanic circulation 
would continue much as it does now. It is possible that 
the angular velocity of the sea-surface is diminished by the 
moon’s unequal attraction to a greater degree than is the 
velocity of the solid globe. If the velocity of rotation of 
the ocean has been diminished one-thousandth part more 
than that of the earth, it would account for the westerly 
motion of the ocean surface in equatorial regions. Wind 
is not necessarily the cause of the current observed along 
with it. As local disturbances of equilibrium are every- 
where occurring at the surface of the ocean, if the local 
current tending to restore equilibrium flows more or less 
with the wind, it will do so as a surface current ; if it has 
to force its way against the wind, it will flow as a sub- 
surface current. The author urged owners of large yachts 
to combine to make thorough observations of currents on 
a particular region at particular times. 

Prof. W. Libbey, D.Sc., read a paper on “‘ The relations of 
the Gulf Stream and the Labrador Current,” which are 
especially important as bearing upon the migrations of 
schools of fish. The region off the southern coast of New 
England was chosen for this inquiry, and the 50° I’. curve 
of temperature was a most interesting one. The upper and 
lower waters were dealt with separately. Upper :—The 
boundary between the cold and warm waters at the surface 
is very seldom a vertical straight line. The winds sway 
the surface waters of these currents one way or another, 
it may be for miles, just as they may retard or reinforce 
them in their general direction. The winds here are of 
two classes, south-easterly and north-westerly. The 
tendency of the former is to drive the surface warmer water 
towards the coast, and above the colder Labrador current, 
while that of the latter will have the opposite effect. 
After allowance is made for other factors, the winds are 
the most active causes of the variations here. By the 
accumulation of variations in one direction, it is possible 
that the boundary may be carried far from its normal 
position. Lower portion:—Though the lower waters are 
affected mainly by the larger factors in oceanic movements, 
yet the cumulative effect of minor impulses will be felt by 
them, but the changes in the lower waters will be less rapid 
than in the upper. Neither the 45° line nor the 60° line 
showed any great deflections, thus apparently indicating 


that they are usually well within the boundaries of each | 


of the main bodies of their respective currents. In the 


spring of 1882, the sea from Cape May to Nantucket | 


was covered with millions of the tile-fish (Lopholatilus 
chamaleonticeps), dead or dying, and this fish has not since 
been found there, although the author caught it south of 
Martha’s Vineyard. This is accounted for by changes of 
temperature affecting the sea bottom in certain areas to 
the injury of a fish probably tropical in origin. The dead 


bodies of the fish came to the surface in a long, crescent- | 


like curve, which followed the line of the edge of the 
continental platform between Cape May and Nantucket. 

‘* Geographical Societies and Oceanography ’”’ was the title 
of a paper by Prof. J. Thoulet, in which societies were 
urged to pay greater attention to the geography of their 
respective regions, and, more particularly, societies in 
towns near the sea were recommended to undertake the 
compilation of information relating to the oceanography 
of their adjacent seas. 

Prof. Otto Pettersson described the details of a proposed 
scheme for an international hydrographic survey of the 
North Atlantic, the North Sea, and the Baltic, which he, 
in conjunction with Dr. G. Ekman, had drawn up; and 





| Mr. H. N. Dickson read a paper on the circulation of waters 
| on the east coast of Great Britain, which gave the results 
of the work done by the Jackal expedition of the 
Fishery Board of Scotland, despatched in 1893 in con- 
nection with Prof. Pettersson’s scheme. The fact that 
water of the highest salinity is not found at the surface 
near the eastern coasts of Great Britain points to an 
extremely complex process of mixture taking place at 
lower levels. 

A paper on the counter-current, ‘‘ El Nifio,” on the coast 
of Northern Peru, was read by Senor F. A. Pezet. Great 
uncertainty exists as to the cause or causes of this current, 
which exercises a great influence on the climatic conditions 
of the coast of Northern Peru, and it seems certain that 
the great rainfalls in the otherwise rainless regions of Peru 
have been due to the current. A closer investigation of 
the subject is, therefore, most desirable. 

AFRICA, 

Sir John Kirk’s paper was on ‘The Suitability of 
Tropical Africa for Development by White Races, or under 
their Superintendence.” Though dealing with the whole 
of Tropical Africa, the paper was more especially devoted 
to those portions occupied by England, with the object of 
inviting discussion, and considered (1) the possibilities of 
colonization proper ; (2) the establishment of European 
settlements in places permitting of temporary residence, 
or more permanent residence by a very limited number of 
Europeans; (3) the means whereby the native races may 
themselves be taught to aid in the development of the 
country. The introduction of steam-power and improved 
firearms, and the opening of the Suez Canal, had 
reversed the causes that led to the seclusion of Africa— 
internal misrule, the slave-trade, an inhospitable coast, 
absence of ports, exposure to adverse winds and ocean 
currents, and a bad climate—from which the Arabs, 
Persians, and Indians had an advantage. The Sahara in 
the north and distance in the south also were adverse, but 
the time has now come for Europe to open up Africa, and 
by modern agencies to develop it and teach the negro to 
assist in its development. Five conditions are necessary 
for success, viz. : (1) the climate must approximate to that 
of countries already settled by Europe; (2) aggravated 
malaria must be absent; (3) the country must be capable 
of supporting Europeans, and must also offer additional 
| attractions; (4) these conditions must extend over an 
| adequate area, so that the colony may be sufficiently large 
| for self-defence, etc. ; (5),a rapid means of transit through 
| the unhealthy zone must be found. All maritime zones, and 
districts below five thousand feet elevation, are useless for 
colonization, but in the central plateaux the climate 
compares favourably with that of countries already settled 
by the white races. Early unfavourable experience is no 
criterion, as original conditions can be greatly improved 
by the resources of civilization. The healthy plateaux are 
fertile. On the other hand, healthy districts are sometimes 
| rendered unsuitable by being broken up by intervening 
| belts of malarial country or river valleys, but steamers 
| and railways will give rapid access to the healthy areas. 
| The suitable localities are few. All West Africa is im- 
| possible of colonization, except German South-West Africa, 
| which probably has a good climate and minerals but lacks 
| harbours. Matabeleland, and probably the high plateau west 
of Nyassa and Batokaland, fulfil the desired conditions. 
Masailand, with a railway, and Abyssinia, are the only 
other possible districts. Settlement apart from coloniza- 
tion is, however, everywhere possible, with periodic change 
to Europe and hill-stations. The increase of the native 
races will be a danger that must be guarded against. 
Small colonies of British Indians will afford object-lessons 

















XUM 














Ocroser 1, 1895.) 


KNOWLEDGE. 





221 











that will tend to raise the negro and furnish allies to the 
whites, while giving skilled labour in the hot districts. 
The negro is an eager and ready imitator. 

Count von Pfeil, in a paper on ‘‘ The Development of 
Tropical Africa,” contended that success depended on 
three conditions. (1) A thorough knowledge of each 
district must be obtained by the aid of the geographer, so 
that we shall be able to tell with some degree of certainty 
whether our intended pursuits, agricultural or other, are 
adapted for the country or not. (2) Much attention 
should be given to the study of tropical hygiene, as a 
most important means of making Tropical Africa a healthy 
abode, which will be the greatest step towards colonizing 
it. (3) Make the negro take a share in the labour of 
civilization, which is difficult, but do not rely either on 
force or setting a good example, but teach him to want 
and he will work. As Nature supplies food and shelter, 
there are few material wants he can be taught, so wants 
must be created by removing those things from which he 
suffers, but which will return if he does not aid the white 
man and relapses into an inert state. 

Mr. H. M. Stanley, M.P., though generally agreeing 
with Sir John Kirk, thought his paper looked too far 
ahead. The colonization of Central Africa was not yet 
the question, but the making of it possible in the future 
by commerce, improving the blacks, ete. When in 1876 
and 1877 he saw the Congo expanding and the shallows 
increasing, he was a pessimist, for it seemed impossible 
that the river could be occupied by a flotilla of steamers ; 
but before the end of 1877, with further knowledge, he 
wrote, ‘‘ The time will come when this great river, now 
known for the first time, will be an international question.” 
But in founding the Congo State, they did not lose time 
in studying scientific geography. He had never known a 
colony founded upon scientific geography. What was 
known of scientific geography by Smith, the founder of 
Virginia, by the Pilgrim Fathers, by the founders of 
Australia and New Zealand, or by Cecil Rhodes, who had 
planned colonies so vast as to be the wonder of the 
century? The pioneer must clear the way slowly and 
cautiously, ascertain if the country is livable, and employ 
the instruments of civilization as aids. There were now, 
in sixteen years, forty steamers on the Congo, with eight 
hundred white men, by which the whole of its basin could 
be navigated. Central Africa might be as livable as India or 
Brazil. In the highlands of Ceylon, English families could 
live healthily, and so it might be in Central Africa, which 
with rapid transit, cultivation, roads, hotels, and European 
sanitary arrangements, would be quite different from the 
Africa of to-day. It was so with other tropical regions, and 
why not with Central Africa? Ina certain state in America 
he had had more fevers than in five years in Africa; but 
since then the population had increased fourfold because 
they had learned the art of living, which, and not scientific 
geography, was what was wanted in tropical countries. 
Young men would not learn this, and so died in Africa. 
He had been twenty-three years there altogether, and he 
felt just as strong as if he had never been in Africa; and 
so it was with others. Before young men from the 
universities went to Africa, they should study for some 
months the arts of conquering fevers, warding them off, 
and living wisely. 


Count von Pfeil, in reply, said that as a pioneer he had | 
been a founder of a colony, that of German East Africa, | 


but the work of the pioneer was past, and what was 
wanted now was scientific geography. 

Mr. E. G. Ravenstein considered a study of African 
climatic conditions to be of the first importance, and this 
should be conducted in a systematic and scientific manner. 


| civilization. 


| rule of the Mahdi. 





| From what he knew of these conditions he would not 


advise anyone to found a colony in Central Africa. 
Mr. Silva White concluded that (1) Tropical Africa is, 
on the whole, unsuitable for European colonization. (2) It 


| is capable of only a limited degree of development, as 


compared with other and still undeveloped regions of ths 
world. (8) In order to reach even this restricted stage of 
development, it is essential that the signatory Powers at 
the various African Congresses should carry out in practice 
the excellent enactments for which they are theoretically 
responsible ; that in the absence of reliable native labour, 
imported labour be introduced ; and that railways be built 
from the nearest base on the coast to the chief centres of 
European settlement in the interior. (4) Very few regions 
are, in the absence of mineral wealth, capable at the present 
day of returning a reasonable interest on expended capital. 
(5) The opening up of Africa must follow the lines of least 
resistance. The most favourable direction is from the 
south, next from the east, and then from the west. (6) 
Speaking generally, Tropical Africa may be profitably 
exploited by the European Powers, provided they cordially 
unite in adopting an uniform progressive programme, and 
are able to solve the labour problem. 

M. Lionel Décle’s paper assumed that Europe’s partition 
of Africa can only be excused by the good we may do 
to the natives. For the natives there are only blacks and 
whites, and it ought to be so with us. All our efforts 
ought to be directed towards developing trade and agricul- 
ture. Railways would do more towards civilization than 
soldiers or missionaries, but they are costly, and take long 
to build. Six feet roads, instead of native winding foot- 
paths, should be opened out to begin with, and be furnished 
with a good supply of water every ten or fifteen miles. 
Along these roads, at intervals of one hundred or one 
hundred and fifty miles, small trading stations should be 
established, with market places and fixed market days. 
The native labourers should be paid in cash, and a currency 
introduced. Traders to establish stations might be sub- 
sidized and provided with six armed policemen for each 
station, and an escort of soldiers to accompany caravans 
to and from the coast. Elephants should be protected, 
both for ivory and to serve as beasts of burden, and an 
international commission should settle disputes between 
the Powers. 

Slatin Pasha said that, during the sixteen years he had 
been in Africa, many regions had been made accessible to 
In most of these, from the establishment of 


military posts, trade is becoming more active. From the 


| east and the west, England, Germany, France, and Italy, 


are on the point of joining hands in Central Africa. 
Tribes formerly quite wild are beginning to respect the 
advancing Powers, and some are contemplating alliances. 
The Soudan, in the middle of Africa, which no European 
can now cross, was for sixty years open to civilization, 
and in Khartoum the Powers had their representatives, 
while travellers of all nations could pass through the region 
safely. By the aid of religious fanaticism, Mohammed 
Akmed united the tribes and overthrew the Kgyptian 
government. Khartoum fell, and with it its bravest 


_ defender, General Gordon, but the greater part of the tribes 


of the Soudan now desire to be freed from the oppressive 
Slatin Pasha then gave an interesting 
account of his escape from his eleven years of captivity. 
Mr. H. M. Stanley, replying more especially to Mr. 
Ravenstein and Mr. White, said, despite all the theorists 
and pessimists, Africa was bound to be opened up. Africa 
had been cursed by the sand of the Sahara and by slavery, 


| and now it seems as if it is going to be cursed by an army 
| of pessimists. 








222 KNOWLEDGE. 


. 


[Octoser 1, 1895. 








M. Victor de Teruant presented a paper on “ French 
Africa, its present and future,” in which it was maintained 
that French settlements were not merely strategical 
positions but genuine colonies. The geographical position 
of France compels her to devote her attention to Africa, 
and her aim, like that of England, is to develop the 
resources of that continent. ‘The Sahara will be trans- 
formed in time by means of the development of the fringe 
of valuable areas around it. The conquest of French 
Africa will be effected by economic and scientific, and not 
by military means, and two of the contemplated operations 
are the raising of the low-water mark of the River Senegal, 
and a trans-Saharan railway. 

General E. F. Chapman, in a paper on ‘‘ The Mapping 
of Africa,’ gave a sketch of the progress of topographical 
surveys there, and urged their extension. Travellers 
would do more useful work by sketching areas rather than 
lines of road, and suggested that information respecting 
places fixed astronomically should be published, and that 
concerted steps should be taken to fix more points 


with the requisite accuracy. By the telegraphs many | 


important places may be fixed from time differences, and 
thus a large number of satisfactory determinations of 
longitude may be obtained within a comparatively short 
time. 

Mr. Silva White read a paper on a crestographic map 
of Africa, in which a new system of cartographic 
expression is introduced, indicating political as well as 
physical factors by which the comparative value of African 
regions to any European Power is shown by ‘cresto- 
graphic’ curves. Thus are brought out into high relief 
the areas of highest resistance against Kuropean domina- 
tion, and the areas of highest relative value to the 
European Powers, indicating, therefore, the lines of least 
resistance against Huropean domination in Africa. 

LIMNOLOGY, 

Prof. F’. A. Forel’s paper on ‘‘ Limnology as a Branch 
of Geography” contended that the study of lakes is a 
science, and a distinct branch of geography, for a lake is an 
isolated and distinct geographical individual with its own 
peculiar chemical conditions, its own inhabitants, its own 
littoral, pelagic, and deep societies of organisms. Limno- 
logy is well adapted for specialization, for its study comprises 
hydrography, geology, petrography, hydrology, climatology, 
chemistry, temperature, optical properties, and biology. 

A paper by Dr. H. R. Mill, on “‘ The Limnology of the 
British Islands,” after referring to the occasional and 
unsystematic study of lakes in the past, gave instances of 
the exaggerated ideas of the depth of lakes that were 
common. Loch Morar, one thousand and eighty feet deep, 
is the deepest lake in the British Islands, while in an 
extensive area of Derwentwater, said to have depths of 
ferty fathoms, it was found that two fathoms was the 
maximum. A large number of temperature observations 
have been made in Loch Lomond and other neighbouring 
lakes, and measurements of lake-level are observed at 
Derwentwater, Loch Katrine, Thirlmere, and the artificial 
lake, Vyrnwy. The depth of many lakes has been officially 
ascertained, and as a result of the soundings made by the 
author and Mr. Heawood in 1898-4, on Windermere, 
Ullswater, Derwentwater, Bassenthwaite, Buttermere, 
Crummack Water, Ennerdale Water, Wastwater, Coniston 
Water, and Haweswater, the sub-lacustrine contours of 
about twenty square miles were determined, and are now 
being placed by the Ordnance Survey on the official maps 
on the scale of six inches to one mile, and they are 
published in the (‘eographical Journal for July and August, 
1895. 

M. Paul Vuillot contributed a paper on the Niger 


lakes which had been discovered through the French 
occupation of Timbuktu. Lake Fagibine is fifty-five 
miles long, with a maximum width of fifteen miles, and 
communicates by a narrow passage with Lake Tele, which 
extends south toGundam. Their hydrography is peculiar. 
The waterway connecting the lakes with the Niger has a 
current, the direction of which varies according as the 
water is higher in the Niger or in the lakes, thus forming 
a natural reservoir for storing flood water, and maintaining 
the current of the river in the dry season. There is a 
third lake, called Dauna, south of Lake Fagibine, but it is 
only known from native reports. 


A VOYAGE TO VICTORIA LAND. 


The subject of Antarctic Exploration was resumed by a 
paper by Mr. C. E. Borchgrevink, giving an account of his 
voyage to Victoria Land in the Antarctic. As the 
expedition was for whaling, few instruments could be taken. 
Melbourne was left on September 20th, 1894, and they met 
with their first snow on October 18th, on the night of which 
day there was a magnificent aurora. An immense barrier 
of ice, forty to sixty miles long, was sighted on November 
6th. With level top and perpendicular sides, it attained 
an elevation of six hundred feet above sea level. At 55° 
S. the albatross and Cape pigeon had left them, but not the 
stormy petrel. On December 7th the edge of the pack 
ice was seen, and they then shot their first seal. Subse- 
quently multitudes of marine animals were seen. Belenny 
Island, with its lofty peak of twelve thousand feet, in 
64° 44’ §., was seen on the 14th, and the sun was just 
touching the horizon at midnight on Christmas eve. On 
the 26th the Antarctic Circle was crossed, and on January 
14th, in 69° 55’ S., they came again into open water, after 
having spent thirty-eight days in working through the 
pack. Cape Adair, on Victoria Land, in 71° 23’ 8., was 
sighted on the 16th. The cape consists of a square mass 
of basaltic rock, three thousand seven hundred and seventy- 
nine feet high, and from it the coast extends to the west 
and south as far as the eye can reach, with ice-covered peaks 
that rise to twelve thousand feet, and glaciers so numerous 
that twenty were counted close to the Bay of Adair. 
Possession Island, in 71° 56’ S., on which Ross had landed 
fifty-four years before, was found to be covered with a thick 
layer of guano, and to consist of volcanic rock rising to three 
hundred feet, with vegetation at thirty feet above sea level, 
while the surface was remarkably free from snow. On the 
22nd they reached 74° S., and then turned north and landed 
next day on Cape Adair, the first landing on Victoria Land, 
when penguins were found to be abundant up to one 
thousand feet above the sea. Temperature observations 
showed a minimum of 25° F. and a maximum of 46° F., 
while the water in the ice pack was 28° F.; but at South 
Victoria Bay it was above freezing point, showing a warm 
north-running current. Within the Antarctic Circle the 
barometer at 29 always indicated calm and beautiful 
weather. A specimen of rock of quartz, felspar, and 
garnets, pointed to economic minerals. An expedition 
could safely winter at Cape Adair, where everything 
indicated less rigorous conditions, and where meteoro- 
logical observations might advantageously be made. He 
was willing to lead a land-party to work to the South 
Magnetic Pole. An expedition ought not longer to be 
delayed, since the scientific results might be of the greatest 
importance. 

Dr. John Murray thought the importance of the paper 
could not be exaggerated. The interior of Victoria Land, 
being a high pressure area, might have greater evaporation 
than precipitation, and it was possible there might be an 
annual vegetation. 





YUM 








XUM 





Ocvoser 1, 1895.} 


GEOGRAPHICAL ORTHOGRAPHY. 

Mr. G. G. Chisholm, M.A., read a paper on “ The 
Orthography of Place-names,”’ in support of the proposal of 
the Congress to appoint a committee on the subject. Such 
a committee would have to consider, firstly, how far it is 
desirable to adopt the principle of transliteration in place 
of phonetic writing, for the Russian and Greek present 
peculiar difficulties in the way of adopting the phonetic 
principle. Again, what signs are to be used for certain 
sounds which have no exact equivalents in the scheme of 
orthography to be employed? What, too, is to be under- 
stood by the “ local pronunciation ’—that usually heard at 
the place, or that of an educated speaker of the country ? 
In China different dialects are spoken by the educated over 
wide areas, and the peculiarities of one or other of these 
dialects are frequently extended to the writing of all 
Chinese names. 

Dr. J. Burgess followed with a paper on ‘‘ Geographical 
Place-names in Europe and the East.”’ 

A paper was then read on “ The Transliteration and 
Pronunciation of Place-names,’”’ by Dr. G. Ricchieri, who 
dwelt on the importance of uniformity. 

CARTOGRAPHY, 

General Sir Charles Wilson brought up reports on 
Prof. Penck’s proposal for a map of the world on the 
scale 1: 1,000,000, which scale was approved, and it was 
recommended that the sheets be limited by parallels and 
meridians, and that the projection be tronconique. The 
size of the sheets is of less importance, and so left to 
discussion, but the meridian of Greenwich and the metre 
as the unit of measurement were approved. Prof. De 
Lapparent favoured the reports, but Mr. Ravenstein 
thought Great Britain, Russia and the United States 
would not issue maps with the metre for a unit. Prof. 
Wagner thought the time had not yet arrived for such a 
map, and Prof. Schrader expressed an opinion entirely in 
its favour. 

A report from the Geographical Society of Marseilles 
was presented by MM. Fabry and Leotard, expressing 
approval of the proposed map and submitting various 
desiderata. 

M. Elisée Reclus submitted the following proposals for 
the construction of a globe on the scale of 1: 100,000. 
(1) Take stock of existing well-made relief plans on scales 
not smaller than 1: 100,000; (2) reduce them to the 
scale of 1: 100,000, with the real proportions in height 
and place; (8) complete them by construction of relief 
maps of the intermediate regions; (4) proceed to the 
construction, at one of the great centres of the world, of a 
spheroid of 1: 100,000, showing correct relief of countries 
surveyed, and approximate relief of the rest of the surface ; 
and protect the spheroid by a covering giving the true 
external appearance of our planet, and furnish it with 
fittings to facilitate study and general use. 

Signor Césare Pomba proposed that the construction of 
terrestrial globes in relief shall be discontinued ; that all 
globes shall be constructed on a scale of an even number 
of millionths of natural size, the numerator of which is 
divisible by two, five, or ten, and that all globes shall, like 
maps in sheets, show the scale with the corresponding 
diameter and circumference. 

Herr Fritzsche described the method of cartography 
employed in executing the Siegfreid-Lochman map, which 
has been called the map of the future, and which combines 
artistic with geometric methods of representing land forms. 

The forthcoming new ethnographical map of Europe 
was described by its author, Herr V. von Haardt. It will 
be on the scale of 1: 3,000,000, and measure six feet eight 
inches by five feet ten inches. 


KNOWLEDGE. 223 











SPELEOLOGY AND MORPHOLOGY OF THE EARTH, 

‘* Speleeology, the Science of Caverns,’’ was the title of a 
paper by Mons. E. A. Martel. The scientific investigation 
of caves dates only from the end of the eighteenth century, 
when it was first undertaken for paleontological purposes. 
Although much good work has been done in the British 
Islands, Moravia, Hungary, the Karst, and in France, 
there is still much room for improvement in the methods 
of investigation before speleology can lay claim to rank as 
a science. Abimes, or swallow-holes, were described, and 
it was shown that speleological investigation would be 
of value to many branches of natural science, and even in 
England and Ireland much remains to be done by British 
speleologists. 

Prof. Penck read a paper on “The Morphology of the 
Karth’s Surface.” The morphology of the earth’s surface, 
like that of living beings, has to do with forms which are 
subject to constant changes. The problems dealt with 
are, therefore, not stereometric but essentially genetic. 
Changes in the form of the earth’s surface result (1) from 
removal of material, ‘‘ erosion,’ which is ‘ true erosion ” 
when at the points of the greatest application of force, and 
‘‘ denudation ”’ when at the points of least resistance ; (2) 
from addition of material, ‘‘ accumulation”; (8) from 
movements of the earth’s crust, ‘“ dislocation,” through 
faulting or folding. From this change are (1) the formation 
of new portions of surface, or the deposit of material on 
existing surfaces; (2) the destruction of existing surfaces 
by removal, or covering with new matter ; (3) the alteration 
of existing surfaces so that they acquire a new character, 
as in the transformation of a plain into a mountain slope 
by folding. 

Papers and reports were also presented to the Congress 
on the following subjects :—Bosnia and Herzegovina; the 
limits of Continents; exploration in New Guinea, 
Australia, and Madagascar; climatology of Portuguese 
and Spanish Colonies of West Africa; the sea route to 
Siberia ; life and works of Cassini de Thury; the geo- 
graphical element in evolution; fundamental lines of 
Anatolia and Central Asia; the most northern Eskimos ; 
ancient charts; medieval manuscript maps; study of the 
Basques; an international cartographic association ; laterite 
and red-earth in India and Africa; the Pyrenees and the 
new methods of surveying; the Spanish Sierra Nevada ; 
the definition of geography a3 a science ; geography and 
the economic and agricultural crisis; an international 
bibliography of geography. 

Resolutions were approved by the Congress respecting 
the retention of office by officers of the Congress, geo- 
graphical publications, method of writing foreign names, 
the mapping of Africa, Prof. Penck’s proposed map of the 
world on the scale of 1: 1,000,000, cartographic catalogues, 
survey of the Baltic, North Sea, and the North Atlantic ; 
an international observation of earthquakes, geographical 
education, registration of literature, dating of maps, and 
the decimal system. 

The next meeting of the Congress was fixed to be held 
in 1899 at Berlin. It was announced that there would be, 
in 1897, a colonial exhibition in Portugal, in commemora- 
tion of the five hundredth anniversary of Vasco da 
Gama. 


The Congress was concluded on Saturday, August 38rd, 
by a report on its proceedings by the Chairman of Com- 
mittees, Major Darwin, and a valedictory address from the 
President, Mr. Clements Markham, congratulating the 
members on the success of the meeting, and expressing 
the hope that their deliberations would be of great value 
to geographical science. 








224 KNOWLEDGE. 


[Ocroser 1, 1895. 





< 





LIGHTNING PHOTOGRAPHS. 





Photograph taken during the storm of August 22nd, 1895. 


A number of interesting photographs of lightning have 
been taken during the 
severe thunderstorms of 
this summer. The first 
of the two which are 
reproduced in Kwnow- 
LEDGE this month was 
taken by Mr. George 
Primavesi, at Tooting, 
during the storm of 
Thursday, August 22nd, 
at about 9 p.m. The 
plate was exposed for 
one second only, and 
during that time but one 
flash occurred, which, 
as will be seen in the 
photograph, was much 
distributed. The second 
photograph was taken 
by Mr. H. J. Adams, at 
Beckenham. Although 
a much smaller flash, 
it is an exceedingly 
vivid one. 





Photograph of a vivid flash taken at 
Beckenham. 








COAL MINE EXPLOSIONS AND COAL MINE 
FIRES; THEIR OCCURRENCE AND 


SUPPRESSION. 
By D. A. Louis, Mem. Fed. Inst. Min. Eng. ; Mem. N. of 
Eng. Inst. Min. Mech. Eng.; Mem. Amer. Inst. Min. Eng. ; 
Mem. Min. Assoc. & Inst., Cornwall ; dc. 


ESIDES sharing with other kinds of mining many 
of the risks incident to such operations, coal 
mining is, unfortunately, distinguished by having 
dangers peculiar to itself. These dangers arise 
from the character of the material mined, which 

exhibits inflammability, friability, porosity, and prone- 
ness to association with combustible gases. The last of 
these is the primary cause of all fire-damp explosions, 
whilst to the other three we may look for an explanation 











of coal-dust fires, and for spontaneous combustion in 
coal mines. 

These three phenomena—fire-damp explosions, coal-dust 
fires, and spontaneous conflagrations—may be regarded as 
pertaining particularly to coal mines; for, although gas 
explosions occasionally occur in metalliferous mines, such 
occurrences are rare. One or other of these phenomena is, 
moreover, accountable for nearly all the calamities that 
have ever befallen mankind in the pursuance of such 
industrial operations. Consequently, coal mining is very 
generally regarded as a particularly unattractive and 
perilous occupation, and really this is not to be wondered 
at, when one pictures the scene of a coal mine explosion—a 
labyrinth of narrow passages pervaded by a pernicious 
atmosphere, deep under the ground, only accessible from the 
surface by one or two holes of comparatively insignificant 
horizontal dimensions, but of great depth, the only illumi- 
nation from feeble lamps scarcely equalling a candle in 
power. Under such circumstances the sudden and appar- 
ently unaccountable appearance of one of the catastrophes 
—a gas explosion, for instance—presents a truly awful 
picture, with its irresistible rushing current of flame, 
smoke, and débris, carrying merciless destruction wherever 
it can gain access; this being succeeded by utter darkness 
and a poisonous atmosphere, that asphyxiates those who 
have by chance survived the force of the explosion-wave. 

But in spite of the truly terrible character of explosions, 
and the apparent unattractiveness of the occupation, coal 
mining, as a matter of fact, as carried on in the majority 
of mines now-a-days, is not particularly perilous, and, so 
far from being unattractive, even exerts a kind of fascinating 
influence over many people. The writer of this paper is 
acquainted with many individuals who really delight in 
working in coal mines. In well-conducted mines, and 
where circumstances permit, the passages are neither 
tortuous nor very low, the atmosphere is excellent, and the 
surface can be reached in a shorter time than it takes 
to reach the upper part of a house of three stories ; while 
the chances of an explosion are reduced to a minimum, so 
that such occurrences are rendered as near to impossible 
as human efforts can make them. This comparative safety 
is attained by paying rigorous attention to all the points 
that scientific investigation has from time to time indi- 
cated as necessary, and to which attention will be drawn 
later on. 

Coal mine explosions have occurred ever since mining 
operations have been followed underground, and, un- 
fortunately, we still find them occurring, for but recently 
have we not read with horror the account of the explosion 
at the Albion Mine? Such disasters have naturally 
always awakened strong feelings of sympathy and terror, 
and emphatic demands for investigation ; consequently 
they have been the subject of constant inquiry. Their 
consideration has been the object of much labour of 
commissions and committees, both British and foreign, 
and they have provided a field of perennial fertility to 
numerous investigators in practical science, ambitious of 
earning distinction for themselves and at the same time of 
doing good to mankind. 

In perusing many of these records one is struck with 
the positiveness of the statements made, and with the 
remarkable diversity of the opinions expressed, so that 
one cannot help thinking that to this has been due the 
long survival of coal mine explosions. We can, perhaps, 
never altogether prevent mining disasters, but provided 
we have unanimity in the views as to what is and what is 
not dangerous, adequate precautions could and would be 
undoubtedly adopted everywhere. 

Fire-damp explosions and spontaneous conflagrations 





XUM 








XUM 


Octoser 1, 1895.] 





KNOWLEDG 225 














have attracted attention ever since the early part of the 
seventeenth century, whilst the recognition of coal dust as 
a significant factor in coal mine catastrophes is of 
comparatively recent date. 

Fire-damp explosions were the first to receive the 
attention of a scientific society, and there is a record of a 
gas explosion in a mine in the Philosophical Transactions 
of the Royal Society in the year 1677. 

At that period, however, miners generally ascribed the 
presence of noxious gases in mines to supernatural agencies, 
and strange and remarkable papers appeared from time to 
time in various journals on the subject. As one result of 
these inquiries, it became known that the fire-damp explo- 
sion was caused by a flame coming in contact with the 
mine gas. Ag it was impossible to work in a coal mine 
without light, either some means had to be found to get 
rid of the gas in fiery mines, or the mine had to be 
abandoned. One method adopted was to draw air from 
the surface to take the place of the dangerous air. Thus 
we find, as early as the middle of the seventeenth century, 
that a fire in a special air shaft was used for this purpose. 
The air became rarefied in this shaft, and so upset the 
equilibrium that existed, the denser air in the working 
shaft ran down into the mine, sweeping the gas-laden air of 
the mine before it, and forced it into the air shaft, where 
it, in its turn, became rarefied and found its way upwards 
to the open air. This method of dealing with fire-damp is 
still in use in some mines, but, instead of a mere fire, 
furnaces are employed as the source of heat, and pre- 
cautions are taken to prevent any explosive air from the 
mine becoming ignited, and so causing disaster. Later 
on, the idea suggested itself of destroying the fire-damp by 
burning—a practice still in vogue in some few places; 


whilst, during the latter half of the eighteenth century, | 


chemical means were suggested for achieving the same 
object. 
But about this period Spedding had discovered that fire- 


damp really did not catch alight so readily as had been | 


supposed; that, in fact, the temperature at which it 
ignited was relatively high, actual flame being required to 
ignite it, and mere red heat being insufficient for the 
purpose. Up tothis time we have seen that the treatment 
of the fire-damp question was restricted to the elimination 
of the fire-damp, and that no attention had been paid to 
the character of the light employed. This discovery of 
Spedding opened up a new field, and led to the invention 
and introduction of his steel mill, which is illustrated 
in the next column. 

It consisted of a metal framework carrying a steel disc, 
which was mounted on a horizontal axis, having attached 
to it a pinion, whilst a spur-wheel was mounted on a 
second horizontal axis so as to engage the pinion. The 
spur wheel was set in motion by a cranked handle, and 
caused the rapid revolution of the steel disc, against 
which a piece of flint was closely held, and the shower of 
sparks thus produced provided the illumination, which was 
intended to be of sufficiently low temperature to prevent 
the ignition of fire-damp. This light, however, proved 
feeble and fitful, and by no means safe. But attention 
had now been drawn to the advantage of employing some 
means of preventing the ignition of fire-damp. Hence it is 
we find lamps introduced by Humboldt in 1796, and Clanny 
in 1806, in which the air necessary for supporting the 
combustion of a candle or oil flame had to bubble through 
a layer of liquid on its way to the flame, thus isolating 
the flame from the air in the mine. In some other lamps, 
also, the products of combustion had to pass through a 
layer of liquid. 

Such lamps, however, were awkward to manipulate, 











cumbersome and unsuitable for coal mining, and although 
this was a move in the right direction, yet a satisfactory 
means of illumination, coupled with non-ignition of the 
fire-damp, had not been discovered. The question of the 
ignition of the fire-damp was, however, soon attacked by 
Sir Humphry Davy from another point of view—that is, as 
to the circumstances attending an explosive ignition. It 





The Steel Mill. 


was he who found that the fire-damp alone would ignite 
without explosion, and that even when mixed with varying 
proportions of air up to eighty-five per cent., it did not give 
rise to explosion, whilst with more air it became explosive, 
increasing in violence as the percentage of air became 
greater, until the air constituted eighty-nine per cent. of 
the mixture, but from this point onwards the explosiveness 
of the mixture diminished until it contained ninety-four 
and a quarter per cent. of air, when it again ceased to be 
explosive, and with larger proportions of air either burnt 
quietly or not at all. The most dangerous proportions he 
found to be eleven to twelve per cent. of fire-damp. 

It now became generally admitted that gas explosions 
in mines were due to air containing from about five to 
fifteen per cent. of fire-damp becoming ignited by contact 
with flame or intensely heated gas, and thenceforth the 
question, which had hitherto been treated in a haphazard 
manner, could be dealt with in a rational way. ‘T'wo 
problems were thus presented for solution. 

Firstly, how to dilute the treacherous atmosphere of a 
mine below the dangerous limit, and secondly, how to 
light the mine without running the risk of igniting the 
gas. These problems alone have furnished an inexhaustible 
supply of work for the investigator and inventor. 

The method of treating the first of these problems was 
to induce more external air to enter and circulate through 
the mine, and this led to the introduction of various 
means to supplant the furnaces already alluded to, and 
we find steam jets, piston air pumps, rotary air pumps, etc., 
employed in their turns with varying degrees of success. 
At the present time fans are the means almost universally 
adopted for forcing in, or drawing through, the coal mine 
the requisite quantity of air for keeping the atmosphere 
below the dangerous limit of combustibility. 

It is sufficient to note here that these fans have been 








226 KNOWLEDGE. 


[Octoser 1, 1895. 








aE Neen ea ae 


brought to an advanced stage of efliciency. An idea of the 
improvement in this direction may be gathered from the 
fact that in the early decades of this century, the currents 
of air, in what were then considered well-ventilated mines, 
travelled at a rate of about five feet per second, or a mile 
in seventeen and three-fifth minutes, whilst in our days, 
currents travelling thirty feet per second, or at a rate of a 
mile in less than three minutes, are found in parts of 
mines. Obviously currents of such high velocity are neither 
required nor sustained throughout a mine—in fact, the 
miners would probably disapprove of working in a stiff 
breeze—but such currents are nevertheless encountered, 
whilst some notion of the immense quantity of air that 
modern fans are capable of dealing with will be obtained 
by reference to examples furnished in a recent number of 
the Transactions of the Federated Institution of Mining 
Engineers (Vol. VI., p. 189) ; there we find descriptions of a 
fan, capable of propelling more than one hundred thousand 
cubic feet per minute, or sufficient air to change the 
entire atmosphere of Westminster Hall thirty times an 
hour. 

It can well be imagined that the question of dealing 
satisfactorily with this small artificial storm is one of 
great importance to the mine manager, and has received 
considerable attention ; indeed, the problem of diluting the 
atmosphere of a coal mine may be regarded at the present 
time as resolving itself into a question of the economic and 
effective employment of the vast volumes of air that are 
caused to sweep through the mine. Itis generally admitted 
that the best use of this vast volume of air is made by 
“ splitting ” it, that is, causing it as it enters the mine to 
split up, by placing at appropriate spots directing screens, 
each having an aperture that can be adjusted to any desired 
size; the great main current thus becomes divided into 
several smaller currents of a magnitude that can be varied 
so as to provide each section or district, into which the 
mine is for the purpose divided, with sufficient fresh air 
thoroughly to ventilate it. In this way the men in each 
set get fresh air, and in case of explosion the disaster is 
generally limited to one section only, instead of jeopard- 
izing the whole mine. Then, large and straight galleries 
with smooth walls cause less waste of air current than 
small crooked galleries with rough walls. 

The air currents are, of course, expensive to maintain, 
and as it would be wasteful to have them too strong and 
hazardous to have them too weak, it becomes a matter of 
considerable importance that their strength should be 
properly gauged. This is done by taking the temperature 
with a thermometer, their pressure by means of a water- 
gauge, their velocity by means of an anemometer, and 
testing them for the presence of marsh gas after traversing 
the workings. There is, however, some diversity of opinion 
as to the proper manner and the best means of taking the 
velocity and pressure, and this, therefore, is another point 
in the ventilation question that remains to be decided, but 
itis satisfactory to find that differences of opinion as regards 
the diluting problem are restricted now to what may be 
regarded as refinements and not of vital importance. 
Therefore we may regard the present position of this 
point of our subject as satisfactory. 

Referring now to the second problem, namely, how to 
light the mine without running the risk of igniting the gas, 
it may be pointed out that gas does not always come off 
regularly, but occasionally may be given off in excessively 
large quantities, and so for a time render the atmosphere 
of a mine or district of a mine dangerous ; this is quite 
sufficient to demonstrate the need of considering the 
second problem. 

This problem, like the first, was scientifically atlacked 





by Sir Humphry Davy, and although George Stephenson, 
who subsequently invented the locomotive, was simul- 
taneously and independently studying the same problem, 
and brought out an early form of his safety lamp, called 
the ‘Geordie,’ yet to Davy is due the invaluable dis- 
covery that the explosion would not pass wire gauze. This 
was in the year 1815, and since that time a vast amount 
has been done by a host of experimenters and discoverers 
towards the elucidation of this problem—indeed, so much 
thought and ingenuity have been expended on the con- 
struction of the safety lamp with such fruitful results, 
that any adequate treatment of it would require a separate 
article; for in spite of the multitude of such devices 
already introduced, new ones are constantly appearing, but 
the old principle of having gauze at the air inlets and 
outlets is adhered to. In the illustration below, the old 
Davy lamp and the recent Ashworth-Hepplewhite-Gray 
lamp are shown side by side. The former, it will be seen, 
consisted of an oil vessel A, upon which was screwed a 
ring Bb, supporting a cylinder of gauze F, which surrounded 






























































Sir Humphry Davy’s Lamp. 


The Ashworth-Hepplewhite-Gray 
Lamp. 


the flame, and had an extra gauze cap at G ; the supporting 
rods I kept the gauze in place, and the top plate protected 
the lamp from falling objects, and the-miner’s hand from 











XUM 














XUM 


OcrozeR 1, 1895.] 


KNOWLEDGE. 227 








the heat of the lamp. The other lamp is shown in section. 
The flame of the lamp is surrounded by glass; but if the 
course of the arrows is followed, it will be seen that the 
air, both on entering and leaving the combustion chamber, 
passes through gauze, indicated by broken lines. 

At present it is sufficient to state that with the increas- 
ing speed of air currents of the improved ventilation, the 
simple Davy lamp soon proved unsafe, and has been 
unanimously condemned by the various commissions 
appointed to inquire into the matter in England, France, 
Germany and Austria. 

The Davy lamp and many of its successors gave a very 
feeble light, and hence the various efforts made to improve 
the light-giving power of safety lamps. But much increase 
of lighting power never appears to be attained without the 
introduction of some disadvantageous element, and it is 
a question whether a safety lamp has yet been discovered 
which is really efficient in all points, although there are 
many that are safe under most conditions obtaining in 
coal mines. Many people think that it is for electricians 
to solve the problem. This may possibly be correct, but 
as yet electric lamps are defective in one or two points— 
a very important one being that to which attention is now 
to be drawn—the detection of fire-damp, choke-damp, and 
white-damp, in the atmosphere of coal mines, a point 
which, considering the intimate connection existing between 
the first of these gases and fire-damp explosions, and 
between the other gases and loss of life or injury to health, 
is naturally of paramount significance. 

Ever since the importance of adequate ventilation has 
been recognized, the advisability of being able to test the 
atmosphere of a coal mine for dangerous gases has also 
been admitted. It is well known that a safety lamp flame 
only burns normally so long as the atmosphere is 
moderately pure. When it becomes mixed with other 
gases, to even a small extent, the flame of the lamp 
becomes altered in appearance. It elongates, and is 
surmounted by a feeble luminous flame known as a “ cap,” 
which increases in size with the proportions of fire-damp. 
Between two and a half and three per cent. of fire-damp 
in the atmosphere has in this way a visible effect on the 
flame of an ordinary safety lamp burning oil. As, however, 
any interruption in the ventilating current, or a small 
additional emission of gas, or the presence of dust, is 
capable of rendering such an atmosphere very dangerous, 
it has been everywhere accepted that it is necessary to 
keep the fire-damp in the atmosphere of dusty and fiery 
coal mines below one per cent. 

Fire-damp detectors of greater delicacy than the ordinary 
safety lamp have become necessary, and have from time 
to time been introduced. In them various properties of 


fire-damp have alternately been called into requisition, in | 
| still, one cannot help thinking that simple precautionary 


order not only to indicate the presence of this objectionable 
gas, but also to show the extent to which it is present, 
even when only amounting to less than one quarter per 
cent. Some of these indicators are designed to examine 
in the laboratory samples of air previously collected in the 
mines, whilst others indicate on the spot in the mine 
itself the proportion of fire-damp present in the atmosphere. 
The latter are evidently the more appropriate for daily 
use, and to these alone attention will be drawn here. 
The Pieler lamp is a large Davy safety lamp, burning 
alcohol. This lamp has served well the purpose of a 
delicate portable indicator of fire-damp; but being by no 
means free from danger, it has undergone considerable 
improvement at the hands of Chesneau, and has been 
made very much more efficient, so that the flame now 
exhibits a change of colour, as well as the production 
of a “cap,” in the presence of gas. Yet it does not give 











unqualified satisfaction, as it is a non-illuminating lamp, 
and necessitates the carrying about of an extra lamp for 
lighting purposes. As a matter of course this point has 
received attention, and attempts have been made to over- 
come this detrimental feature. 

It has been known for some time that a hydrogen flame 
is a still more delicate indicator than an alcohol flame. 
It, therefore, occurred to Prof. Frank Clowes that by 
having within an ordinary safety lamp a little burner 
that could be fed as required with hydrogen, the latter 
would ignite at the oil flame, which could then be 
extinguished by drawing down the wick in the ordinary 
way, by means of the pricker ; the amount of fire-damp, 
even though it was only a quarter per cent., could then be 
readily gauged by measuring the height of the cap. The 
oil flame could then be re-established by pushing the wick 
up, the hydrogen flame turned off, and the lamp used in 
the ordinary manner for lighting. Prof. Clowes has 
successfully accomplished all this in the lamp illustrated, 
and provides a portable supply of 
hydrogen sufficient to make a large 
number of estimations of fire- 
damp, the hydrogen being con- 
tained under pressure in the small 
steel cylinder which, when 
attached to the lamp, not only 
furnishes a reservoir for the neces- 
sary supply of fuel for the delicate 
testing flame, but also acts as a 
convenient handle by which the 
lamp may be held up for exami- 
nation. More recently two 
engineers, M. Legrand in France 
and Mr. Stokes in England, have 
constructed lamps on the Clowes 
principle, in which, however, the 
testing flame is supplied with 
alcohol instead of hydrogen. Hydrogen Oil Testing 

It now seems imminent that the Lamp. 
present position of this section of 
the fire-damp question, like the ventilation section, is a 
question as to which refinement shall be used in order tomake 
us utilize in the best manner the knowledge and appliances 
we now possess, and we may look forward to the battle of 
indicators to keep us posted with the most recent experiment 
and results in this important section of the question. 

As regards fire-damp explosions, therefore, we are at 
present not only conversant with the conditions under 
which they are likely to occur, but we have means provided 
to prevent their occurrence—still they occur! ‘There are, 
of course, unforeseen risks against which we cannot 
provide, and which may account for some accidents ; but 








measures should be more generally adopted, and, if 
necessary, enforced by legislation. 





Sctence Notes. 


angie 

Madagascar (that island which is attracting a good deal 
of attention at present) lies almost entirely within the 
southern tropic, and is one of the largest islands of the 
world, its length being about one thousand miles, and its 
average width two hundred and fifty miles. ‘The tops of 
its highest mountains are not much more than eight 
thousand five hundred feet above the level of the sea. 
The vegetation of Madagascar may be said to be arranged 
in three zones—first, the tropical plains, varying in width, 
and extending inland from the sea-coast; second, forest 








228 KNOWLEDGE. 


(Ocroser 1, 1895. 





. 


lands, of varying extent in different parts, which surround 
the third or treeless zone in the interior. The Rev. R. 
Baron, for many years a missionary in the island, bas given 
an account of its vegetation in the Journal of the Linnean 
Society. He estimates the tract of country covered by forest 
to be about thirty thousand square miles, or one-eighth of 
the island, but destruction of trees by the natives is taking 
place with great rapidity. For exsmple, no fewer than 
twenty-five thousand were cut down to make room for the 
passage of a tombstone quarried at a distant place. Dr. 
Wallace, in his “‘ Island Life” and ‘‘ Darwinism,’ insisted 
on the diversity of the vegetable productions of Madagascar 
from those of the neighbouring African continent, but recent 
researches on the flora seem to show that it is essentially 
African, although it contains a large endemic element. 


Some time ago, one of our correspondents was informed 
of ‘‘an extraordinary squirrel” to be seen in a well-wooded 
part of an estate on the confines of Westmorland and 
Lancashire. On interviewing the gamekeeper, who in this 
instance bapyens to be an intelligent naturalist, he found 
that there was in the woods a squirrel of normal character, 
except in its tail, which was perfectly white. After several 
long and silent vigils, well out of sight, our correspondent 
was rewarded with a sight of the squirrel, a male, in 
company with a female. The reports had in no way been 
exaggerated. The animal was of ordinary size and colour 
except for its tail, which was perfectly white. This is, no 
doubt, a very unusual cccurrence. It was seen by our 
correspondent, and there was nothing of the ‘ cream 
colour’ peculiar to the coat of the squirrel later in 
the year. On a neighbouring estate the squirrels have 
developed extraordinary carnivorous propensities, destroying 
young birds by dozens. Had they confined their depreda- 
tions to ordinary wild birds, the ‘‘ acquired habit ’’ might 
have become hereditary, and even infectious ; when they 
attacked the young pheasants, however, their fate was 
sealed, and an order has gone forth to ‘clear out the 
equirrels.” Mr. Lydekker,in British Mammals, of * Allen's 
Naturalist’s Library,” p. 171, bas referred this occasional 
habit of squirrels to “only a depraved taste,” which, 
however, does not account for its origin, or for the 
undoubted fact that it is a taste more prevalent than is 
generally believed, and therefore “ more honoured in the 
breach than in the observance.” 


M. Piltsechikoff, in describing recent photographs of 
lightning, names three types of flash—‘ band-lightning, 
tnbe-lightning, and watersrout lightning.’’ The first two 
he found to occur in all storms, the third he met with once 
only. From the measured width of the band-lightning on 
photographs, and the computed distance, he estimates the 
actual widths to be from about fifteen to eighty yards. 








Notices of Books. 

Finger-Print Directories. By Francis Galton, F.R.S. 
(Macmillan.) Three years ago, Mr. Galton gave, in his 
‘* Finger-Prints,” an account of the patterns of thumb and 
finger marks, and discussed their bearings on questions of 
heredity and racial distinction. In the present volume he 
shows conclusively that these patterns admit of easy 
classification, and offer a simple and trustworthy means of 
identification. To take a pattern, the tip of a thumb or 
finger is lightly rolled from one side to the other upon a 
slab having printers’ ink upon it, and is then pressed upon 
paper or cardboard. Impressions are thus obtained of the 
papillary ridges, well seen at the bulbs of the fingers and 
thumbs, and the directions, terminations, and junctions of 








the printed ridges can afterwards be examined at leisure by 
means of a lens, and classified. It is estimated that the 
chances of two finger-prints being identical is less than 1 
in 64,000,000,000. Two finger-prints exactly alike may, 
therefore, be safely concluded to be prints from the same 
person ; hence the patterns furnish a sure method of 
proving identity. The difficulties in the way of the 
application of this method of identification have gradually 
been overcome by Mr. Galton, who shows in the volume 
before us how finger-prints can be indexed so as to be found 
as easily as a householder can be discovered by reference 
to a directory. The present writer can personally testify 
to the efficiency of the methods described. A few weeks 
ago he went to the Anthropometric Laboratory at South 
Kensington, and, after giving his finger-prints in the usual 
manner, asked to be identified, as his impressions had 
been taken about four years previously, and had been put 
away with his name upon them. In less than three 
minutes Mr. Galton’s assistant had examined the new 
impressions, and had picked out from more than two 
thousand cards the one containing the old prints and the 
name of the writer. A readier method of identification 
could hardly be desired. How the result is attained may 
be learned from the pages of the book under review. The 
legal profession generally should add the book to their 
libraries, and the prison officials, under whose direction 
finger-prints of criminals are now taken, will find it 
essential to the right understanding of their duties. We 
would finally remark that the collection and investigation 
of finger-prints is open to everyone, and with Mr. Galton’s 
new volume, containing fac-similes of finger-prints and full 
explanations of what they teach, a student will be enabled in 
a short time to become an experienced finger-print detective. 

The Migration of British Birds. By Charles Dixon. 
(Chapman and Hall.) Apart from the deep interest which 
must be attached to any book dealing with the migration 
of birds and their dispersal over the globe, Mr. Dixon’s 
present work should commend itself to every ornithologist 
on account of the freshness in the manner in which the 
subjects are treated. We can but admire Mr. Dixon for 
his boldness in advancing new theories absolutely con- 
tradictory to those already advanced and generally accepted 
by other naturalists, yet we regret the way in which he 
unnecessarily doubts the correctness of observations made 
by men whose experience should be at least as good as his 


‘own. The book is divided into two parts; the first and 


larger portion dealing with the dispersal of birds, and the 
second with their migration. Mr. Dixon dwells at some 
length on past geographical mutations and glacial epochs, 
and it is chiefly upon these and a ‘‘ New Law of Dispersal ” 
that he bases his conclusions. The main feature of the 
book, and one which is carried all through it, is what the 
author is pleased to call a ‘‘ New Law of Dispersal.” A 
new theory would have been a more correct term than 
“law,” for we cannot see that Mr. Dixon has brought 
forward a sufficient number of facts to prove the correct- 
ness of his “law.” Briefly stated, Mr. Dixon’s “ New 
Law ”’ is that northern hemisphere sp-cies of birds never 
increase their range in a southern direction, and that 
southern hemisphere species never increase their range 
in a northern direction. This law, says the author, is 
proved by the fact that there is no immigration route (of 
northern hemisphere birds) which trends south in spring 
or north in autumn. But before we can recognize the 
proof of the law, we have to accept as true the author’s 
statement that the present migration of a species is a 
recapitulation of the past range expansion of that species. 

With regard to the general phenomenon of migration, 
which so many have sought to explain, we do not think 


XUM 











Aave(ri 











Octoser 1, 1895.] 


KNOWLEDGE. 229 








that Mr. Dixon’s theory is so happy as some others. He | 


supposes that the ‘‘ route” is remembered and recognized 
from the great height at which the birds travel by 
certain landmarks, river-valleys, etc., and that it is then 
“ taught to the young while journeying south in company 
with the old birds in autumn.” 
points out (p. 263) that ‘‘ migration progresses day and 
night.” How can birds see the landmarks and river- 
valleys at night when they often travel, as has been 
proved, at a height of two cr three miles above the earth ? 
Again, Mr. Dixon tells us that birds cross the North Sea 
and other wide water areas. What guides them on these 
occasions? Beyond these objections we have it on the 
authority of Herr Giitke, of Heligoland, who for more 
than fifty years has watched migration from the best 
station in the world, that in many species the young 
precede the old birds. 


this fact. There is, unquestionably, some as yet un- 
discovered faculty or sense which directs birds on 
migration. 


Although some of his conclusions are illogical, Mr. 
Dixon’s book is replete with interesting suggestions and 


But Mr. Dixon himself | 





3ut Mr. Dixon seems to doubt | 


he established chemistry as an exact science, and reduced to 
order the chaos of facts concerning the reactions between 
different substances. The story of the work of this giant 


| among the sons of science is the story of one whose life 


was devoted to the extension of natural knowledge. Asa 
man, his character was full of interest ; and as a chemist, 


| his work commands the admiration of all scientific students. 
| Born on September 6th, 1766, at Eaglesfield, Cumberland, 


Dalton attended the village schools there until eleven years 
of age. A year later he opened a school of his own, and 
from that time up to his death he earned his living by 
teaching. His earliest observations were of meteorological 
changes ; and the instruments he used in these first 
beginnings, as in his later scientific work, were home-made. 
Not until 1798 did he become connected with Manchester, 
in the town hall of which a life-size statue of him faces 
one of Joule, who is to modern physics what Dalton is to 
chemistry. After serving six years as tutor in an academy 
at Manchester, he resigned his post, and, while working as a 
private teacher, devoted his spare time to scientific inquiry. 


| Limits of space prevent us from tracing the work that led 


facts, and possesses a number of valuable tables ; and, in | 


conclusion, we would heartily recommend it to the general | 


reader as a work of much interest, and to the ornithologist 
as one that deserves his careful study. 

Analytical Chemistry. By N. Menschutkin. Translated 
from the third German edition by J. Locke. (Macmillan.) 
Menschutkin’s name is faiiliarto English chemists, and 
he and Mendeléeff have done much to increase foreign 
appreciation of Russian investigators. The Russian 
original of the present volume has been well received 
in that country, and has passed through five editions, 
but the translator has preferred the German edition 
for presenting the book to English readers. From a 
comparison of this translation with a copy of the 
fifth Russian edition, we have come to the conclusion 
that the work of translation has been well done. 
Some very interesting chapters in the Russian original 
on the analysis of minerals, and on the volumetric 
determination and separation of bases and acids, have, 
however, been entirely omitted from the English 
edition. Menschutkin’s book fully justifies its chief 
claim, i.e., ‘‘ to teach the student the art of chemical 
thought.’ The very clear system of classification, and 
the lucidity of the details, make it an indispensable 
text-book for the beginner as well as a most useful 
book of reference for the advanced student of chem- 
istry. It is to these two main features that its wide 
circulation all over the Continent, and especially in 
the universities of Germany, must be attributed. 
In gravimetric determinations, the basic precipita- 
tion for the separation of the metals of the III. group 
is not treated as fully as it deserves, and no mention 
is made of the quantitative estimation of lithium, 
though it is very essential for the analysis of mineral 
waters. Some minor errors have been found in some 
of the melting and boiling points (pp. 90, 125, 145, 
149, 205, 225). Of greater importance for the practical 
analyst are a few errors as to the solubility of some 
of the salts (pp. 32, 135, 140, 182, 198, 208). 
Drawings of apparatus are very much missed, since 
they wou'd have added considerably to the convenience 
of the book. 

John Dalton and the Rise of Modern Chemistry. By Sir 
H. E. Roscoe, F.R.S. (Cassell&Co.) The nameof John 
Dalton is known and revered throughout the scientific 
world. By the discovery of the laws of chemical 
combination, and the foundation of the atomic theory, 





to the atomic theory, which is the foundation-stone of 
chemical science. At the end of an essay read before the 
Literary and Philosophical Society of Manchester in 1808, 
a table was given ‘of the relative weights of ultimate 
particles of gaseous and other bodies.’’ This was the first 
published table of atomic weights, and it exhibited the 
fact that, while atoms of the same element have the same 


Joun Datrton, F.R.S. 








230 KNOWLEDGE. 


(Ocrosger 1, 1895. 








weight, atoms of different elements have different weights. 
Sir Henry Roscoe shows, by means of notes found in 
the possession of the Manchester Literary and Philo- 
sophical Society, that ‘‘it was the application of the 
principle of the Newtonian atom to the constitution of the 
gases contained in the atmosphere that led Dalton to his 
atomic theory.”” Dalton died on July 27th, 1844. Man- 
chester, where he resided for fifty years, has done honour 
to his memory, not only by securing the fine statue of 


him which now adorns the grand entrance of the magnifi- | 


cent town hall, but also by establishing a scholarship for 
scientific research. To those who think that great 
cleverness is essential to success, we commend Sir Henry 
Roscoe’s sketch of Dalton’s life and work. And especially 
would we call attention to what Dalton himself remarked 
in his later life. ‘If,’ said he, ‘‘I have succeeded better 
than many who surround me, it has been chiefly—nay, I 
may say, almost solely—from unwearied assiduity.”’ It 
only remains for us to say that the book is an admirable 


one to put into the hands of every young student of 


science. 

Solution and Electrolysis, By W. C. D. Whetham, M.A. 
(University Press, Cambridge.) This handy little volume 
is one of the up-to-date Cambridge natural science 
manuals which are being edited by Mr. Glazebrook. 
Notwithstanding Mr. Pattison Muir’s admirable translation 
of Ostwald’s ‘‘ Solutions ’’ and Prof. Palmer’s edition of 
Nernst’s “‘ Theoretische Chemie,” a short epitome of the 
recent work done on the border-land between chemistry 
and physics has been needed for many years, and Mr, 
Whetham has already shown, although still a young man, 
by his papers on the velocities of the ions, and other work, 
that he is fully conversant with this modern development 
of physico-chemistry. If we except, in addition to the 
author’s own work, that of Ramsay and his pupils, 
Pickering and a few others, this new science evolved from 
the application of the gaseous laws to the phenomena of 


solution and osmotic pressure, although so fruitful on the | 


Continent, has received little attention at the hands of 
English investigators. We therefore hope that Mr. 
Whetham’s book will be read by many of the younger 
men, and that it will induce them to turn thcir attention 
to what is undoubtedly destined to be of considerable 
importance in modifying our ideas about matter and its 
motion. Some years ago the British Association appointed 
a committee to inquire into the subject of electrolysis, 
and the discussions which took place at that time helped 
in crystallizing the ideas concerning the freedom of the 
ions in electrolysis and their behaviour under electrical 
pressure. The extension of these generalizations to solution 
phenomena has followed since that date, so that the two 
subjects of solution and electrolysis are very fitly included 
in the present volume. 
the book are the tables of electro-chemical properties 
which conclude it. 





celia aces 
BOOKS RECEIVED. 
The Herschels and Modern Astronomy. By Agnes M. Clerk 
(Cassell ) Illustrated. 38s. 6d. The Century Science Series. 
Justus Von Liebig, his Life and Work. By W. A. Shenstone 
(Cassell.) Illustrated. 3s, 6d. The Century Science Series. 
The English Lakes. By Hugh Robert Mill, D.Sc. (Philip & Son.) 


Illustrated, 38s 6d. 
Philips’ Systematic Atlas and Philips’ Handy-Volume Atlas. By 
E. G. Ravenstein. (Philip & Son.) 
Consider the Heavens: A Popular Introduction to Astronomy. 


By Mrs. W. Steadman Aldis, (Religious Tract Society.) Llustrated. 
Notes on the Nebular Theory. By William Ford Stanley. (Kegan 
Pau.) Illustrated. 
The Origin of Plant Structures. By Rev. Geo. Henslow. (Kegan 
Paul.) 5s. The Laternational Scientific Series, 


| 


| Society.) 





Not the least valuable portion of | 








Analytical Key to Flowering Plants. By Franz Thormer 


(Swan Sonnenschein.) 2s. 

Hidden Beauties of Nature. By Richard Kerr. 
Illustrated. 

A Laboratory Manual of Organic Chemistry. By Dr. Lassar-Cohn. 
Translated by Alex. Smith, B.¥c., ke. (Macmuillan.) 8s. 6d. 

Report on the Total Eclipse of the Sun observed at Mina Bronces, 
Chile, on April 16th, 18938. By J. M. Schaeberle. 
State Office.) Illustrated. 

A Study of the Physical Characteristics of Comet Rordame. By 
W. J. Hussey. 

Shakespeare. By David Charles Bell. 
3s. @d. Bell’s Readers. 

Elements of Modern Chemistry. 
Fifth Edition. 
Keeler. ( Lippincott.) 


(Religious Tract 


(Hodder & Stoughton. 
By Charles Adolphe Wurtz. 


Illustrated. 





THE VISIBILITY OF CHANGE IN THE MOON. 


3y H. G. We ts, B.Se., Author of the ** Time Machine.” 


HE absolute quiescence of the lunar crust is a 
commonplace of popular science; it is, however, 
open to doubt whether the belief in the permanence 
of the lunar surface has all the justification its 
wide acceptance might lead us to expect. This 

conclusion has been drawn from the absence of any percep- 
tible change in the forms of lunar contours, and of any 
visible eruptive phenomena. But it must be remembered 
that fairly extensive changes of contour may have occurred 
before the epoch of lunar photography, and that even now 
the displacement of relatively large masses has a very fair 
chance of escaping notice. As Mr. Elger has pointed out, 
objects as large as Monte Nuovo or Jorullo might come 
into existence in many regions without anyone being the 
wiser, and a catastrophe as extensive as the destruction 
of Herculaneum and Pompeii might still escape detection. 
And few people outside astronomical circles probably 
appreciate the peculiar consequences the physical conditions 
of our satellite’s surface would have upon the phenomena 
of voleanic eruption. 

The most striking features of a typical volcanic eruption 
upon our planet are certainly the tumultuous noises of the 
outbreak, and the enormous clouds of steam and pumiceous 
ashes that rush out of the vent and spread over the 
country encircling the volcano. These cloudy masses 
form a background to reflect and exaggerate whatever 
incandescence may be visible within the crater. But upon 
the moon all this pomp of smoke and fiame would be 
absent, because upon the moon there is no atmosphere to 
buoy up the finely divided products of the eruption, and 
whatever the voleano threw out would, so soon as the 
velocity of its projection was lost, fall back at once upon 
the lunar surface. The uprush of flames, which is another 
striking accompaniment of terrestrial outbreaks, would also 
be absent, since a flame rushes upward only because it is 
specifically lighter than the air through which it rushes. 
The intense cold of the lunar surface, together with the 
absence of atmospheric pressure, would also conspire to 
rob any incandescent gas of its visibility, for so soon as it 
was released at the vent it would expand and cool, and so 
elude our observation. A momentary disclosure of incan- 
descence is all we can anticipate under the most favour- 


| able circumstances, and in the bright glare of the lunar 


day—and it is only the lunar day we are accustomed to 
observe—it is conceivable that the equivalent of the most 
violent terrestrial eruptions might be going on in the field 
of our largest telescope without attracting attention. 

Even could one stand upon the moon itself near the 
vent, the phenomena of an eruption in progress would still 
be far less awe-inspiring than u on this planet. Ina pro- 


(Sacramento : 


Revised and Enlarged by W. H. Greene and H. E. 











YUM 




















XUM 


Octoser 1, 1895.] 


KNOWLEDGE. 231 











found silence and in the unmitigated glare of the sunlight 
we should see the molten rock creeping sluggishly from 
the lips of the crater, and in the place of the explosive 
escape of volumes of steam the surface of the lava flow 
would merely be agitated by the bubbling out of what 
would immediately become a frosty garment of snow and 
carbon-dioxide. It would be little more terrific than the 
squeezing of paint from a tube. The forcible and sustained 
ejection of scoriz and ashes on a terrestrial volcano is due 
largely to the effervescent escape of superheated steam 
from the molten magma; but if the lunar surface is, as is 
generally supposed, somewhere near the absolute zero of 
temperature, then the isotherm of the freezing point of 
water must be some considerable distance beneath the 
crust, and the boiling point isotherm still deeper. In 
which case the expansive force of the contained water may 
be much less in a lunar than in a terrestrial crater, and 
indeed it may be insufficient to spray up or even vesiculate 
the more viscous lava flow. On the other hand, however, 
the feebler gravitational energy of the moon and the absence 
of a superincumbent atmosphere would enable a much 
smaller expansive force to project masses to a considerable 
altitude, and a far smaller force of upheaval to rupture a 
much greater thickness of overlying crust. The Innar 
eruption would be therefore, one may think, more of the 
nature of one violent explosion like the discharge of a gun, 
and nothing more, rather than the sustained pyrotechnic 
display of a terrestrial outbreak. 

Taken altogether, these considerations point to the 
conclusion that a lunar eruption, if such a thing is still 
possible, would consist essentially of two phases; the 
first, the very transient one of breaking through the crust, 
would eject any obstacle in the vent to an enormous 
altitude, the ejected rock or rocks, in a more or less 
pulverized condition, raining back immediately about the 
volcanic vent, and then might follow an inconspicuous 
and noiseless bubbling and guttering out of snow and frozen 
gas, and (less probably) lava within the lips of the crater. 
The former scarcely more than the latter could be expected 
to be visible from this planet. 

But it must be borne in mind that these are purely 
speculative suggestions, involving finally the groundless 
implication that the moon has differences of internal 
temperature, and so some lingering vestiges of internal 
energy. There is plausibility in the belief that at the 
absolute zero of temperature matter will have lost all its 
inter-molecular energy, and, among other things, that it 
will not be able to contract further. If we assume that 
not only the unilluminated surface of the moon, but its 
very centre also, has sunk to that final static state, then 
the voleanic forces due t> the contraction of a cooler 
exterior upon a warmer nucleus do not come into play. 
But along another line the grounds for anticipating lunar 
changes are less hypothetical. There mast still be super- 
ficial displacements due to the expansions and contractions 
which the monthly passage of the solar heat-wave must 
cause, and there is not only pariodic heating and cooling 
of the lunar surface, but since no matter is perfectly rigid, 
there must also be a tidal deformation due to the sun’s 
attraction. These influences, at any rate, whatever we 
may think of the volcanic possibility, must produce tiltings 
and instabilities, and in the tremendous impact of 
meteorites—for the moon, unlike the earth, has no 
pneumatic protection from such jars—we have a force 
more than adequate to start landslips and overthrow the 
tottering summits of cliffs. Altogether there is plentiful 
a priort ground for denying that the moon is indeed an 
immutable dead world beyond all further indignities of 
change. 








And this is not merely an a priori proposition, for 
about twenty years ago there is every reason to suppose 
that a black spot appeared near Hyginus, and in 1866 a 
certain amount of discussion centred about the crater 
Linné. The floor of Plato has also been suspect, but 
vithout any very decisive results. Assuredly there can be 
no more promising field of observation for the amateur 
astronomer in possession of a fairly powerful telescope 
than a detailed study of some definite portion of the lunar 
disc, and an exhaustive comparison with the accumulating 
collection of photographic charts that have been made 
during the past decade. To see the side of some mighty 
crater suddenly slide and crumble into ruin, or some gaping 
chasm opening in a dazzling slope of white, has so far been 
the lot of no terrestrial observer. Yet it may be that 
already such change has happened in the field of some 
watching telescope, and only escaped observation because 
the eye that watched was set against the expectation of 
change. And even as this is written some happy mortal 
may be detecting the faint stirring, the scarcely perceptible 
movement that marks the still living forces that have so 
far been hidden from our eyes. But the chances are that 
whatever changes may be proceeding will be detected in 
a less dramatic way—by the systematic measurement and 
comparison of photographic charts extending over a 
considerable period of years. 





THE SIZE OF THE SOLAR SYSTEM. 
By J. E. Gore, F.R.A.S. 


S my readers are aware, the solar system consists 

of a number of planets revolving round the sun as 

a centre, and of subordinate systems of satellites 

revolving round the planets, or at least round some 

of them. Our own earth is one of these planets, 
the third in order of distance from the central luminary, 
which forms the common source of light and heat to all 
the members of the system. In addition to the planets and 
satellites, there are also some comets which form permanent 
members of the solar system. Some of these comets 
revolve round the sun in very elongated orbits, while the 
planets revolve in nearly circular orbits. A consideration 
of the absolute size of this planetary system and its relative 
size compared with that of the universe of stars, or at least 
the universe visible to us, may prove of interest to the 
general reader. 

To determine the size of the solar system it is, of 
course, necessary in the first place to ascertain the dimen- 
sions of the planetary orbits with reference to some 
standard, or unit of measurem2nt as it is termed. Tne 
unit of measurement adopted by astronomers is the sun's 
distance from the earth. As the earth is the third planet 
in order of distance from the sun, this distance is, of course, 
an arbitrary unit. We might take the mean distance of 
Mercury from the sun as the unit, but as we refer all our 
measurements to terrestrial standards, and the diameter of 
the earth is used in the measurement of the sun’s distance, 
it is found more convenient to take the sun’s distance from 
the earth as the standard of measurement for the solar 
system and the distance of the stars. 

The relative distances of the planets from the sun have 
been determined by astronomical observations and are 
represented approximately by the following figures, the 
earth’s mean distance from the sun being taken as unity: 
Mercury 0:387, Venus 0°723, the earth 1-, Mars 1°523, 
the minor planets 2:08 to 4:262, Jupiter 5:203, Saturn 
9588, Uranus 19:183, and Neptune 30:055, or taking 
the earth’s mean distance from the sun as 1000, the 








232 


KNOWLEDGE. 


[Ocroser 1, 1895. 








> 


distance of Mercury will be represented by 887, Venus 723, 
Mars 1528, the minor planets 2080 to 4262, Jupiter 5203, 
Saturn 9538, Uranus 19,183, and Neptune 30,055. These 
are the mean or average distances, the orbits not being 
exact circles but ellipses of various eccentricities, that of 
Mercury—among the large planets—being the most 
eccentric, and that of Venus the least so. Among the 
minor planets, the eccentricities vary from 0, or a perfect 
circle, to 0°44, the value found for a small planet discovered 
by M. Wolf in November, 1894. 

The first scientific attempt to determine the sun’s 
distance from the earth seems to have been made by 
Aristarchus, of Samos. His method was to note the 
exact time when the moon is exactly half full, and then 
to measure the apparent angle between the centres of the 
sun and moon. It is evident that when the moon is half 
full the earth and sun, as seen from the moon, must form 
a right angle with each other, and if we could then 
measure the angle between the sun and moon, as seen 
from the earth, all the angles of the right-angled triangle 
formed by the sun, moon and earth would be known, and 
we could deduce at once the relative distances of the sun 
and moon from the earth. This method is, of course, 
perfectly correct in theory, but in practice it would be 
impossible, even with a telescope, to determine the moment 
when the moon is exactly half full, owing to the irregu- 
larities of its surface. Aristarchus had no accurate 
instruments, and no knowledge of modern trigonometry, 
but by means of a tedious geometrical method he concluded 
that the sun is nineteen times further from the earth than 
the moon. This result we now know to be far too small, 
the sun’s distance from the earth being in reality about 
three hundred and eighty-eight times the moon’s distance. 

In modern times the sun’s distance has been determined 
by various methods. The most recent results tend to 
show that the sun’s parallax, as it is termed, cannot diSer 
much from 8°81 seconds of arc. The solar parallax is 
the angle subtended at the sun by the earth’s semi- 
diameter. A parallax of 8-81 seconds implies that the earth’s 
mean distance from the sun is about 92,790,000 miles. 
Multiplying this number by the figure? given above, we 
find that the mean distances of the planets from the sun 
are as follows, in round numbers :—Mercury 35,909,000 
miles, Venus 67,087,000, Mars 141,384,000, the minor 
planets 198,000,000 to 395,470,000 miles, Jupiter 
482,786,000, Saturn 885,105,000, Uranus 1,779,990,000, 
and Neptune 2,788,800,000. This makes the diameter of 
the solar system, so far as at present known, about 5578 
millions of miles. Across this vast space light, travelling 
at the rate of 186,300 miles per second, would take eight 
hours nineteen minutes to pass. 

But vast as this diameter really is, compared with the 
size of our earth, or even with the distance of the moon, 
it is very small indeed when compared with the distance 
of even the nearest fixed star, from which light takes over 
four years to reach us. The most reliable measures of the 
distance of Alpha Centauri, the nearest of the fixed stars, 
places it at 275,000 times the sun’s distance from the earth, 
or about 9150 times the distance of Neptune from the sun. 
If we represent the diameter of Neptune’s orbit by a circle 
of two inches in diameter, Alpha Centauri would lie at a 
distance of 762 feet, or 254 yards, from the centre of the 
small circle. If we make the circle representing Neptune’s 
orbit two feet in diameter, then Alpha Centauri would be 
distant from the centre of this circle 9150 feet, or about 13 
mile. Asthe volumes of spheres vary as the cubes of their 
diameters, we have the volume of the sphere which extends 
to Alpha Centauri 766,000 million times the volume of the 
sphere containing the whole solar system to the orbit of 





Neptune. If we represent the sphere containing the solar 
system by a grain of shot one-twentieth of an inch in 
diameter, the sphere which extends to Alpha Centauri 
would be represented by a globe 88 feet in diameter. 

It will thus be seen what a relatively small portion of 
space the solar system occupies compared with the sphere 
which extends to even the nearest fixed star. But this 
latter sphere, vast as this is, is again relatively small com- 
pared with the size of the sphere which contains the great 
majority of the visible stars. Alpha Centauri is an 
exceptionally near star. Most of the stars are at least ten 
times as far away, and probably many a hundred times 
further off. A sphere with a radius 100 times greater 
than the distance of Alpha Centauri would have a million 
times the volume, and therefore 766,000 billion times the 
volume of the sphere which contains the whole solar 
system ! 

From these facts it will be seen that enormously large 
as the solar system absolutely is, compared with the size of 
our own earth, it is, compared with the size of the visible 
universe, merely as a drop in the ocean. 





PHOTOGRAPHS OF THE CLUSTER MESSIER 
13 HERCULIS. 
By Isaac Roserts, D.8c., F.R.S. 


R.A. 16h. 88m. 6s., Decl. N. 36° 39°0’. 


HE photographs were taken with the 20-inch 
reflector ; that with an exposure of five minutes, 
at sidereal time 16h. 42m., on June 15th, 1895, 
and the other with an exposure of sixty minutes, 
between sidereal time 14h. 51m. and 15h. 51m., 

on May 28th, 1895. 
Scale, 1 millimétre to 6:18 seconds of arc. 
REFERENCES. 

N. G. C. No. 6205, G. C. No. 4230, h 1968. Sir J. 
Herschel, Phil. Trans. 1833, p. 458, Pl. XVI., Fig. 86. 
Lord Rosse, Phil. Trans. 1861, p. 782, Pl. XXVIIL., Fig. 
88, and Obs. of Neb. and Cl. of Stars, p. 150. A. C. 
Ranyard, Know.epGe, Ist May, 1898, pp. 90-98. 

The photograph with an exposure of five minutes shows 
the stars with only a faint trace of nebulosity at the 
central part of the cluster, and that with sixty minutes’ 
exposure shows the central part involved in nebulosity so 
dense that, on the print, the stars cannot be seen in the 
midst of it, though on the negative they are clearly visible. 
The two prints, when correlated, therefore, convey to us 
nearly the same amount of information as can be gathered 
from the negative exposed for sixty minutes. 

Nine photographs of the cluster have been taken by me 
during the past eight years. The first, on May 22nd, 1887, 
is published in Photographs of Stars, Star-Clusters, and 
Nebula, Pl. 84, p. 93. An interval of fully eight years has, 
therefore, elapsed since these and the first photograph 
were taken, and now, by the publication of these photo- 
graphs in a form available like the first, and enlarged to 
the same scale, there is evidently work ready to hand for 
those who take a practical interest in astronomy to correlate 
these new photographs with the earlier one, in order to find 
out what, ifany, change or changes have taken place amongst 
the stars during the interval of eight years. These 
operations can readily be performed by placing the dual 
photographs of 1887 and 1895, that have been exposed 
during sixty minutes each, side by side, and judging by 
eye-alignments of the stars if changes have taken place 
amongst them. Another method is to use a réseau ruled 
on glass, about ten centimétres square, with the inter- 











Knowledge ° 


PHOTOGRAPHS OF THE GLOBULAR CLUSTER, MESSIER 13 HERCULIS. 
By ISAAC ROBERTS, D.Sc., F.R.S. 


Taken June 15th, 1895, with an Exposure of Five Minutes. Taken May 28th, 1895, with an Exposure of One Hour. 


























XUM 











XUM 


Ocroser 1, 1895.] 





KNOWLEDGE. 233 











sections of the lines making two square millimétres each. 
Another method is to use a millimétre rule with a thin 
edge, and a pair of compasses; a circle of about ten 
centimétres in diameter and ruled into degrees upon any 
transparent substance would also be required for the 
purpose of measuring position angles. Armed with these 
simple requisites, much useful astronomical work could be 


done upon the photographs, and if any doubtful points | 


should be met with in the course of the investigations, 
they could be settled by reference to the original positives 





on glass made by enlargement from the negatives, or, if | 


necessary, by reference to the negatives themselves. 
Arrangements are being made to place these glass positives 


at the disposal of the British Astronomical Association, | 


and thus make them readily available whenever required. 

If the work of correlating the photographs, as herein 
suggested, is taken in hand by competent examiners, and 
their results are found to add to astronomical knowledge, 
there are other photographs with intervals of seven or 
eight years between them available for investigation, which 
could be published as occasion might indicate; thus a 
system of astronomical research would be inaugurated, 
that must eventually add largely to existing knowledge. 

The scale of these photographs is such that a change in 
the position of any star with reference to the other stars, 
if it exceeds three seconds of arc in amplitude, ought to be 
detected by careful examination ; and, if no change of 
such small extent as this has taken place in eight years, it 
will be a proof that the object is very distant from us—that 
the stars probably belong to one system, and that we must 
wait for some years longer before we can hope to under- 
stand the physical laws which govern the stars constituting 
these so-called globular clusters. However, we have now 
before us, and fixed with unquestionable accuracy, the 
position and relative brightness of each star in the cluster 
and in the surrounding region of the sky, so that the 
solution of this great problem can only be a question of 
time, and of the repetition of the methods here described, 
or of others of a similar character. 





Nore.—The scale of each of the four photographs of 
nebule published in the September number of Know.epee, 
is given as 1 millimétre to 12 seconds of arc; but the 
photo-printers have not strictly followed the directions, 
and consequently the scale applicable to the four prints is 
1 millimétre to 11 seconds of are. 





Petters. 


[The Editor does not hold himself responsible for the opinions or 
statements of correspondents. | 





MIRA. 
To the Editor of KNowLepGE. 


Dear Sir,—My observations of Mira in the early part 
of this year may perhaps be of some interest in connection 
with the discussions on the subject, though it will be seen 
that the later ones are affected by some uncertainty. The 
resulting magnitudes are derived from the Harvard 
magnitudes of the comparison stars, but that of the ruddy 
star €’ Ceti is corrected for personal equation of colour. 
The column headed ‘absorption’ gives the estimated 
relative absorptive power of the atmosphere, taking 1-0 to 
represent a clear atmosphere. With regard to the result 
on 3 mo. 3, it should be noted that moonlight makes ruddy 
stars look brighter ; but ruddy stars look fainter to me 
than they do to the Harvard observers, and the resulting 
magnitudes are given as compared with white stars. The 











observations were made with the aid of field-glasses, power 
4, out of focus; and all at Sunderland, except that on 
2 mo. 24, which was at Middlesbrough. The effect of 
atmospheric absorption upon the brightness of Mira and 
the comparison stars was taken into account for each 
night’s resulting magnitude. 


a Resulting Absorp- 
Date. GMT. Magnitudes. tion. 


1895, 1 mo. 23.—9.10 5:72 1:0 
25.—9.27 5:98 1 

29.—6.40 14:85 2:5 

2 mo. 11.—6.50 4°45 3:0 

2°5 


19.—7.15 4:23 Not a very certain obser- 
vation, as the smoke in the 
fog may not be uniform. 

94.—8.28 4°98 11 Possibly some irregular 


smoke, but I do not think so. 
11 Moonlight. 


T. W, Backuouse. 


8mo. 8.—7.59 4:86 
Sunderland. 


cpio 
CONCENTRIC RAINBOWS. 
To the Editor of Know Epce. 


Sir,—I recently saw what I believe is rather a rare 
phenomenon. There was a short, sharp shower of rain 
about six o’clock in the evening, and then the sun shone 
brilliantly and a rainbow appeared—not a particularly 
bright one. There was no secondary bow with inverted 
colours, but inside the primary bow were packed, one 
inside the other, no less than three subsidiary bows fading 
imperceptibly into one another. I once, two years ago, 
saw a very bright rainbow with two of these subsidiary 
bows, and also the usual secondary bow. The theory of 
the primary and secondary bows is simple enough, but I 
should be glad if some of your correspondents could give 
an explanation of the theory of these subsidiary bows. 
I gather from what I have seen stated that, provided the 
rain-drops are equal in size, the larger the drops the 
greater is the number of subsidiary bows. 

Artuur Kennepy. 


Ashtead. 


[The occurrence of supernumerary bows enclosed 
within the primary one is by no means common. I have 
only seen these on two or three occasions in many years. 
Once I observed no less than four bows of gradually 
decreasing width, enclosed by and concentric with the 
primary one, the innermost being a faint colourless line. 
There were thus five circular bands, and between their 
widths there was a distinctly proportionate diminution 
towards the centre of the system. On other occasions I 
have seen three or four bands, the inner ones being very 
faint. 

In my experience this phenomenon synchronizes with a 
very stormy and disturbed condition of the air. The 
bands appeared in a higher zone of the sky than the 
ordinary rainbow is seen in, but not so high as that of 
the white* rainbow, which at times occurs in the cirrus 
region. I once saw one of these latter at a vast elevation 
gradually concealed from sight by a moving drift of cloud 
underneath it, the obscuring cloud being itself far above 
the region of the ordinary bow. 

It would appear that these involved bands, which usually 
show little colour, indicate the depth and thickness of the 
bank of rain cloud, or rather the zone of watery particles 
originating them. If so, they naturally give a valuable 
hint for forecasting weather, as they point to a vast 





* One of these, which was seen January 5th, 1895, was described by 
the writer in Nature. 








234 KNOWLEDGE. 


. 


[Ocroper 1, 1895. 











quantity of water in suspension. It is too often overlooked 


that optical figures in the atmosphere are not really plane | 


but solid figures, geometrically. 


I am not aware that any satisfactory explanation of | 


involved rainbows has been published. My own theory, 
suggested, however, with all humility, is that they show the 
depth of the rain bank, and are a perspective foreshortening 
of rings from the base of an (imaginary) cone of particles, 
and only limited in number by the limits of the refraction 
angles. 

A drop of rain with crystalline nucleus, /.c., nascent hail, 
will give rise to curious optical phenomena. But I do not 
refer these figures to the varying size of rain-drops, a theory 
which badly agrees with the observed proportionate reces- 
sion of the rings.x—Samvuet Barser. 

Elmsett, Ipswich. 





++ 
COLOURS OF BUTTERFLIES. 


To the Editor of KNow.Leper. 


Sir,—It is difficult to reply to Mr. Miller on such com- | 
plex problems with the limited space at my disposal. I | 


will, however, endeavour to state my answers to his 
queries as shortly as possible. 
(1) Mr. Miller says he cannot see the truth of the truism, 


that some insects do not require protection, while others | 


do require it. The answer is that all insects, in order to 
survive, require some form of protection unless their 
power of rapid flight is superior to that of their enemies. 
This protection may take the form of protective resem- 
blances, mimicry, or warning colouring. 

(2) Mr. Miller denies that natural selection is an 


‘*‘ environmental force.” This is merely a question of the | 
meaning of words. Natural selection is, so far as it is | 


accepted, a force or power whereby those individuals, 
which are most suited to their environment, survive in the 
struggle for existence; those less in conformance with 
their environment “going to the wall.” This is a fact, 
whatever name we give to the acting power; the only 
doubtful point is, whether natural selection will explain 
everything. 

(3) Mr. Miller objects to the ‘‘ metaphorical” use of 
the word “mimicry.” This I explained in my last 
letter. Mimicry implies conscious imitation, whereas in 


the cases we are considering there is supposed, by Darwin | 


and Wallace, to be no conscious effort, as Lamarck 


formerly stated. 
(4) Mr. Miller queries how can hereditary transmission 


increase resemblance (i.e.—protective resemblance and | 
mimicry); and how can accidental resemblances be trans- | 


missible? Hereditary transmission is bound to increase 
resemblance in such cases if the species is to survive at all, 
simply because all those of lesser resemblance are killed, 
and only the most modified escape the attacks of enemies, 
In each generation some individuals will have more pro- 
tective resemblance than others ; because no two animals 
are alike, and these only will survive, and thus the 
resemblance is increased in successive generations. 


(5) Mr. Miller again asks, ‘‘ what has this to do with | 


the origin of species?” I can only say that Darwin and 
Wallace’s explanation of the origin of species was given in 


their theory of natural selection, which is briefly as | 


follows: In any animal or plant there is a rapid increase 


of numbers by reproduction; but the total numbers are | 


stationary—hence the struggle for existence. As no two 


individuals are alike, there is variation, and this is trans- | 


mitted by heredity to successive generations. Hence 


| follows the survival of the fittest, leading to the survival 
| only of those best adapted to their environment. By 
means of protective colouring and mimicry, many species 
of butterflies survive and form species, which would other- 
wise disappear. This is what the question has to do with 
regard to the origin of species. 

(6) Mr. Miller’s last query I do not quite follow. He 
seems to imply that butterflies are most exposed to danger 
while on the wing, and asks why are they not protected by 
the colours on the upper surfaces of the wings? This 
really requires no answer. While on the wing, butterflies 
must trust to their powers of flight and take their chance ; 
the most obvious need for protection is while they are 
perching with the wings folded up, especially when the 
female is laying eggs. Hence the under surface of the 
wings is protectively coloured. The upper surface is 
usually bright by sexual colouring to attract the opposite 
sex. 


C. F. Marsuati, M.D. 


ae re 
To the Editor of KNowLEDGE. 


Sir,—I am sorry to see that my letter has made this 
subject no clearer for Mr. Miller. 
| In the first place, respecting the necessity of protective 
colouring, I understand a necessity to be that which is 
indispensable, and thus fail to see how Mr. Miller can at 
one and the same time logically maintain that protective 
| colouring is always necessary and yet that many insects 
exist without it. Too me one statement appears to 
contradict the other. 

Then, as to the difference which he considers I ought 
to make between the protected and the unprotected, I 
would point out that as the economy of no two species is 
exactly alike, no distinct line of demarcation can possibly 
be drawn. Insects displaying the rapid motion of the day- 
| flying moths, or the up-and-down eccentric flight of many 
of our butterflies, would probably be little better off were 
they differently coloured. Those flying only in the night- 
time would in the majority of cases, where their day-time 
habits did not clash, need no special colouring beyond some 
sombre tint ; while again, those inhabiting districts where 
enemies were scarce or not powerful, would have small 
inducement offered for their improvement. 

I think it probable that protective colouring occurs more 
frequently than Mr. Miller supposes. So far as my own 
experience goes, I have found the cases where the colour 
| of an insect is out of all harmony with its surroundings, 
| during each period of its existence, to be the exception 
| and not the rule ; and in such instances contra-balancing 
causes may often be found, such as the unpleasant taste of 
the magpie moth (Abraxas grossulariata). Besides, the 
| evolutionary doctrines demand, not that each form should 
be perfect, but only improving. 

Then Mr. Miller objects to natural selection as an 
| environmental force. I do not know whether he wishes to 
deny the existence of natural selection altogether, or only 
objects to my terming it ‘‘a force.” In the latter case 
what label would he prefer as a substitute? When oil and 
water are mixed together, one rises and the other sinks by 
what we call the force of gravitation ; so, when good and 
bad organic forms are turned out into the world, the strong 
rise and the weak fall, and I can see no objection to 
terming that which makes them rise and fall ‘‘a force.” 

Mr. Miller says he is not aware that any scientific men 
ever employ metaphor in enunciating truth, and adds, 
‘certainly neither Darwin nor Wallace so uses it.’ Surely 
Mr. Miller has not been very observant, or he would not 
have made such a statement. I think it would be hard to 











XUM 











XUM 


OcroseR 1, 1895.] 


find any author who does not employ metaphor toa greater 
or lesser extent, and I am unable to see how objection can 
be raised to the practice so long as everyone understands 
that it is metaphor. Does Mr. Miller wish to condemn all 
who speak of the sun risiny, of the moon setting, or of an 
acid possessing greater elective ajjinity for one base than 
for another ? May I also refer him to Darwin’s “ Origin 
of Species,” page 58 in the sixth edition, where the great 
naturalist devotes a special argument in support of that 
which Mr. Miller condemns. Speaking of the objections 
which had been brought against his use of the terms 
‘‘ Nature” and ‘‘ Natural Selection,” he says, ‘‘ Everyone 
knows what is meant by such metaphorical expressions, 
and they are almost necessary for brevity. ..... With 
a little familiarity such superficial objections will be 
forgotten.” 
Aurrep J. JoHNsoN, 
Boldmere, Erdington. 
HOOKED PROCESS ON BEES’ MANDIBLES. 
To the Editor of KNowLepcE. 


Sir,—May I ask the attention of your readers to the 
curious hooked process on the mandibles of the worker 
bee? I am not at all certain that they have been observed 
before, as I find no reference or mention of them in various 
works on bees, or in Chesire’s ‘‘ Bees and Bee Keeping,” 
which I understand, from an authority at the Natural 
History Museum, is the latest and standard work on the 





yy 
a 2s Se eaten 8 ne 


ee onesie i tlt esata 





\ 














A. Mandible of Worker Bee, showing hooks. 3B. Portion of hooked 
process, more magnifiel. c. One hook still more magnified. 
(Magnified 140 diameters.) 














KNOWLEDGE. 235 


subject. Indeed, they are not easy to make out, as the 
mandible takes a long time to clear—the specimen which 
enabled me to see them had been kept six months in 
turpentine before mounting for the microscope. 

As will be seen by the accompanying illustration, the 
hooks bear a great resemblance to those on the smaller 
wing, which give the name to the Hymenoptera ; they are 
nine in number, and run along a raised rib or buttress of 
chitine, parallel with the cutting edge of the mandible. 
The process begins at the lower end with some hairs, 
which are obviously later on modified, to form the hooks. 
The difference between the hair and the hook is of interest, 
the latter being much shorter and coming abruptly to a 
somewhat blunt end. 

I have no practical knowledge of bees, but if I might 
hazard a guess as to the use of the process (which I do 
with diffidence), I would suggest for the purpose of hooking 
on to the claws of the hind leg of the bee above, when 
clustering. In favour of this view, I find that the hooks 
are absent from the mandibles of the queen bee and of the 
drone ; also from those of the humble bee and the queen 
wasp. The queens and humble bee do not cluster, but I 
am uncertain as to the drone; this is one of the points on 
which your readers might help me. 

The drawing is of the mandible flattened for mounting, 
and gives quite a wrong idea as to the actual shape. 

Water WEscHE. 


92, Richmond Road, W. 





THE VOYAGE OF H.M.S. “CHALLENGER” AND 
ITS ACHIEVEMENTS. 


By H. N. Dickson, F.R.G.S. 


NE of the officers of the famous expedition of the 
Resolution and the Adventure concludes an account 
of the voyage by expressing the pious hope that 
the bright example of his great commander may 
inspire future navigators ‘‘ not only to perpetuate 

his justly-acquired fame, but to imitate his labours for the 
advancement of natural knowledge, the good of society, 
and the true glory of Great Britain.’ It would be inter- 
esting to know how far one of Captain Cook’s shipmates 
would consider the Challenger Expedition a fulfilment of 


‘his desires. We can imagine him finding much food for 


reflection in the ways of the “ philosophers” on board, or 
in some volumes of the ‘‘ Reports’’; but we may be sure 
that along with Cook’s second voyage he would “ not 
hesitate to pronounce it one of the most important that 
ever was performed in any age, or by anycountry.” Such 
a deliverance would receive the unanimous approval of the 
scientific world in these days. 

Although the last volume of the “‘ Challenger Report ”’ is 
amongst the most recent Government publications, the 
cruise itself is rapidly becoming ancient history, for three 
and twenty years is a long time in the history of modern 
science. The Challenger Kxpedition grew out of the 
wonderful results obtained by Wyville Thomson and his 
coadjutors in the F'aroe-Shetland Channel and the North- 
East Atlantic on board the Liyhtning (1868) and the 
Porcupine (1870). These results gave glimpses into a new 
world, and it became clear that if science was ever to have 
an adequate conception of the form or material of the 
earth, or of the forces at work on its surface, this new 
world must be explored with the same untiring patience 
as was necessary in the more familiar regions above sea- 
level. The first step was evidently to make a preliminary 
survey of the whole situation, so as to gain a general view 








236 


KNOWLEDGE. 


[Ocroser 1, 1895. 





> 





of the physical and biological conditions in each of the 
great divisions of the hydrosphere, working, of course, with 
all possible accuracy and detail, yet striving chiefly towards 
a delineation of the leading features. Given an accurate 
outline of the whole, more minute studies of restricted areas 
might follow later, and it would then be easy to place them 
in their proper positions with regard to the whole. This 
idea commended itself strongly to the Royal Society, and to 
many other scientific bodies, and influence was brought to 
bear upon the Government, with the result that in 
1872, H.M.S. Challenger, a corvette of 2306 tons, was 
completely fitted out and furnished with every scientific 
appliance for examining the sea from surface to bottom. 
The ship was in charge of Captain Nares, with a naval 
surveying staff, and a civilian scientific staff under the 
direction of Professor Wyville Thomson; the latter 
consisting of Messrs. H. N. Moseley, John Murray, J. Y. 
Buchanan, R. von Willemoes-Suhm, and J.J. Wild. The 
Challenger sailed from Sheerness at eleven a.m. on Saturday, 
7th December, 1872, and after a voyage touching Madeira, 
the Canaries, the West Indies, Nova Scotia, the Bermudas, 
the Azores, Cape Verde, Fernando Noronha, Bahia, Tristan 
d’Acunha, the Cape, Kerguelen, Australia, Hong Kong, 
Japan, Valparaiso, Straits of Magellan, and Vigo, she 
anchored at Spithead at half-past nine on the evening of 
Wednesday, May 24th, 1876; having in three and a half 
years cruised over nearly seventy thousand nautical miles, 
and made soundings and observations at three hundred and 
sixty-two stations, besides keeping constant magnetic and 
meteorological observations during the whole period. If 
we bear in mind that the Challenger was commissioned to 
explore the sea and not the land, and that her appointed 
task was amply sufficient to occupy all hands, we must be 
surprised at the use that was made of opportunities on 
shore, Lord George Campbell’s ‘‘ Log-letters from the 
Challenger” is full of interesting observations of men and 
things in various countries— much of it reads like an 
extract from the last century voyages, and Prof. Moseley’s 
“ Notes by a Naturalist on the Challenger” contains many 
important contributions to anthropology, notably an essay 
on the gods of Hawaii and their transformation into orna- 
ments, and an account of the inhabitants of the Admiralty 
Islands. The anthropological collections, now in part 
deposited in the Pitt-Rivers Museum at Oxford, are admitted 
to be of the greatest value, and in the hands of Prof. Sir 
William Turner the skeletons and crania obtained by the 
expedition brought to light new facts of the greatest 
ethnological interest. 

But when we come to the oceanic researches, we find 
a wealth of material simply bewildering. Immense 
collections of zoological and other specimens were sent 
home by the Challenger from various ports visited, and 
she herself returned to England laden like an ocean 
“tramp.” A commission was organized and charged with 
the work of superintending and directing the examination 
of the collections, the discussion of the observations, and 
the publication of reports. The commission was under 
the command of Sir C. Wyville Thomson until his death 
in 1882, when he was succeeded by Dr. John Murray, 
who continued the work in consultation with a committee 
of the Royal Society, and has now brought it to completion. 
Some six or seven years after Dr. Murray became director 
of the ‘‘ Challenger Expedition Commission ’’ the Treasury, 
alarmed by the deceitfulness of the scientific riches 
accumulated, threatened to cut off supplies altogether. 
Fortunately, the threat was not executed, although the 
last payment of £1600 had to be spun out over six years. 

The completed Report extends over fifty volumes, in 
royal quarto, each having an average allowance of six 





hundred pages and sixty plates and maps. The work is 
arranged in six divisions: I. Narrative; II. Physics and 
Chemistry, including Meteorology ; III. Deep Sea Deposits ; 
IV. Botany; V. Zoology; VI. Summary of Scientific 
Results. Division I. is naturally the work of the members 
of the expedition, and Division VI. entirely from the pen 
of Dr. John Murray. In the others the specimens and 
records were distributed amongst specialists for examination 
and discussion, or, where such did not exist, to scientific 
men who would make themselves authorities in the new 
subjects. In the selection of authors no distinction of 
nationality was made, the sole aim being always to find 
the best man for the work, and we may here add our 
congratulations to Dr. Murray on the achievement of this 
great task, for he has made the Challenger Expedition, not 
only the foundation of the greatest work of its kind in 
existence, but the source of a stimulus to many branches 
of scientific research, which will not cease to be felt for 
many years to come. 

Any attempt to give even an idea of the contents of a 
work twice the size of the “ Encyclopedia Britannica” 
within the limits of a single article must necessarily fail. 
Dr. Murray’s Summary, intended as a guide to the 
wanderer through the volumes of the Report, itself 
occupies over twelve hundred pages ; so we must content 
ourselves with a mere glance here and there. 

The first great service rendered to science by the 
Challenger observations was the collection of sufficient 
deep-sea soundings to make it possible to construct relief 
maps of the great oceans. Although these are still very 
defective in many parts, even where supplemented by 
more recent data, they enabled us to form a fair conception 
of the shape of the sea bottom, with its towering volcanic 
peaks, its boundless undulating plains, and its profound 
abysses. Dr. Murray has himself made a specialty of 
this part of the work, and computes the total area of all 
the oceans at 187,200,000 square miles, and the total 
volume at 323,800,000 cubic miles; the average depth 
being 2080 fathoms, equal to 12,480 feet, or something 
over two miles and a quarter. Amongst other things, the 


| Challenger finally disposed of the fabulous depths reported 





by several investigators. The deepest sounding made was 
4475 fathoms, or about five miles, near the Mariana 
Islands, and we have since found no reason to suppose that 
depths greatly exceeding this will be met with anywhere. 
The nature of the sea bottom forms the subject of an 
exhaustive monograph by the Abbé Renard and Dr. 
Murray. The composition and, above ail, the origin of 
the great deep-sea deposits have presented many problems 
of the highest order of difficulty alike to the geologist, the 
biologist, and the chemist, but a general classification has 
nevertheless been arrived at, the distribution of the chief 
deposits has been mapped, and their origin explained. 
Dr. Murray finds that outside a belt three hundred miles 
from land practically the whole ocean is covered with 
‘‘pelagic’’ deposits, in the formation of which land influences 
have played little or no part. In truly oceanic areas where 
the depth is less than 1700 fathoms (say two miles) 
the bottom is usually covered with ‘ Pteropod ooze,” 
so called from the shells which are characteristic of it. 
Beyond this depth the delicate shells disappear, and there 
remains the chalky-looking foraminiferous 00ze known as 
“ globigerina.”’ Below 8000 fathoms the deposit consists 
of substances wholly insoluble in sea-water, forming a red 
clay chiefly volcanic, which covers over fifty millions of 
square miles, not much less than the whole land surface 
of the globe. It is remarkable, as showing the extremely 
slow rate at which the red clay is deposited, that along 
with it immense numbers of sharks’ teeth, some of them 


wwe 








YIM 











XUM 


Ocroser 1, 1895.) 


KNOWLEDGE. 237 











apparently belonging to extinct species, ear-bones of whales, 
manganese nodules, cosmic dust, and other inorganic 
materials were often brought to the surface. 

We cannot here enter into the vexed question of coral reefs. 
Chiefly on account of observations made on board the 
Challenger, a general feeling arose that Darwin’s “ sub- 
sidence theory’ was inadequate. In 1880, Dr. Murray 
propounded another explanation, maintaining that coral 
reefs have grown up from the tops of submerged and half 
submerged banks and mountains, and between the two 
hypotheses the struggle has been keen and protracted. 
Nearly everybody admits the force of Murray’s arguments, 
but some writers still hold that many reefs have been 
formed in the way suggested by Darwin. 

The deep-sea temperature observations were made by the 
naval officers on board, by means of the Miller-Casella 
thermometer. The inquiry into the errors of these 
instruments, made by Prof. Tait, forms in itself an 
important contribution to our knowledge of the effects of 
great pressures upon various substances. All the tempera- 
ture observations have been published separately in the 
form of curves showing the vertical distribution from 
surface to bottom at each station, and the general result 
was obtained that in the open sea the temperature remains 
practically constant from year to year at all depths exceed- 
ing one hundred fathoms. It was further found that over 
certain large areas the temperature at the bottom was the 
same. In the eastern part of the North Atlantic, for example, 
the temperature at the bottom was everywhere 36:8°, while 
in the western part of the same ocean it was 36°3°. It was 
afterwards shown that these immense stretches of uniform 
temperature were due to the fact that below a certain 
depth communication with warmer or colder areas was 
cut off by submarine ridges. 

The examination of the water samples brought home by 
the Challenger was made by the late Prof. Dittmar, who 
confirmed the conclusion reached by Forchhammer that the 
composition of sea water is everywhere nearly the same, 
except that the amount of lime held in solution increases 
at greater depths. At the same time he gave a more 
extensive and accurate account of the proportions in which 
the various elements are present, introducing many new 
methods and refinements in the course of the extremely 
difficult analyses which had to be made. 

It was thus established that the variable factors in 
different parts of the oceans were chiefly physical, the 
variations of temperature and density being of primary 
importance in all questions of oceanic circulation. From 
an enormous number of hydrometer observations made 
during the voyage, Mr. Buchanan was able to construct 
charts showing the surface density for each of the great 
oceans, and the greatly increased data of recent years have 
not modified the leading features of these in any important 
respect. Mr. Buchanan also determined the salinity at 
the depths at a sufficient number of points to give a fair 
conception of the general distribution, although it has not 
been possible to represent the whole by means of maps. 

Observations of oceanic currents were made on board by 
the naval officers, but the general inquiry into the cir- 
culation of oceanic waters was placed in the hands of 
Dr. Alexander Buchan. The preliminary reports on the 
sea temperature observations had settled the rival claims of 
the gravitation and wind theories as to the cause of currents, 
and it became evident that before the problem of oceanic 
circulation could be profitably discussed, the facts of 
atmospheric circulation at the earth’s surface must be dealt 
with. Dr. Buchan accordingly constructed a new series 
of maps representing the distribution of atmospheric 
pressure and temperature and the prevailing winds in 





all parts of the globe during each month of the year, 
and, thanks to the elaborate observations made on the 
Challenger, he was able to extend the work over the oceans 
with some confidence, and at the same time to contribute 
new facts of fundamental importance to the science of 
meteorology. This done, Dr. Buchan proceeded to the 
oceanic problem, and his Report, an appendix to the last 
volume, is the final publication of the series. It includes 
a number of maps showing the distribution of temperature 
over the oceans at vertical intervals of 100 fathoms, and 
from these, and the known distribution of density, it 
appears that the movements of the great masses of 
ocean water depend directly on the influence of the great 
atmospheric systems resting on the surface. 

Although botany was not specially represented in the 
scientific staff of the Challenger, very considerable collec- 
tions were made by Mr. Moseley. These were chiefly 
insular floras, which have been described by Mr. W. B. 
Hemsley; but the enormous extent of the pelagic flora 
was first fully recognized from the observations made 
during the cruise. 

So far as space occupied in the Reports goes, zoology 
has by far the largest share, occupying no less than forty 
volumes. The number of new forms discovered was 
enormous, but it is remarkable that their description has 
added to our knowledge of special groups rather than 
enlightened us as to the relations existing between those 
already known. The geographical distribution of the 
animals obtained by the Challenger is discussed by Dr. 
Murray in the Summary, and, taken along with the 
further observations of more recent expeditions, the 
results are of extreme interest and importance. The 
observations go to show that while life is nowhere 
absent, the animals living at the bottom in the great 
depths are not representatives of primitive types 
as was expected; and it was found that at depths 
below 1000 fathoms the number of species and genera 
obtained in one haul of the dredge was much larger 
in proportion to the number of individuals than is 
the case nearer the surface. Dr. Murray believes that 
the deeper waters were probably peopled by animals which 
migrated from the level of the ‘‘ mud-line,” or zone 
where the minute particles of organic matter derived 
from the land are deposited on the bottom. The mud- 
line is usually found at a depth of about 100 fathoms, 
and the conditions in its neighbourhood are found to be 
of great uniformity all over the world. A remarkable 
similarity between the faunas and floras of the Arctic and 
Antarctic regions has been traced, many species being 
recorded in both which are not found in the intermediate 
zones. Dr. Murray reviews the whole of the evidence 
connected with the distribution of life, and suggests a 
theory which may serve to explain how the complex 
arrangement observed was brought about. He supposes 
that the more highly organized pelagic animals are the 
descendants of animals which at one time inhabited the 
region of the mud-line. The whole ocean had probably at 
that time a uniform warm climate, and when cooling at 
the poles began, in all likelihood in Mesozoic times, 
animals with pelagic larve would die out or seek warmer 
latitudes ; hence in the tropics we find the remains of a 
universal shallow water fauna. At the same time, the 
lower temperature at the poles would cause descending 
currents of colder water in those regions, and these, taking 
a supply of oxygen downwards with them, would make 
life for the first time possible below the mud-line, and 
permit of gradual migrations into the deeper waters. 

We would fain linger over Dr. Murray’s fascinating 
Summary, the only part of the whole work where, in 








238 


KNOWLEDGE. 


[OcroseR 1, 1895. 








gathering up the threads, it has been permissible to 
introduce an element of speculation, and enable us to form 
some picture of the earlier ages in the earth’s history; a 
picture strange beyond any that the imagination alone 
could have conceived. But we must deny ourselves, and 
only express the hope that after so great a work our 
country may not be patriotically puffed up, but may con- 
tinue to take its fair share—a large one—in those further 
researches which have so largely added to the value of the 
Challenger Reports, which were in great part the outcome 
of her memorable cruise. 








THE FACE OF THE SKY FOR OCTOBER. 
By Hersert Santer, F.R.A.S. 


UNPOTS and facule are still fairly numerous, 


though of course they are decreasing in magni- | 
| disappearance of the fourth satellite at lh. 23m. a.m. On 


tude. Conveniently observable minima of Algol 
occur at 10h. 45m. p.m. on the 20th, and at 7h. 84m. 
p.M. on the 28rd. 

Mercury is too near the Sun to be visible till quite the 
end of the month. On the 31st he rises at 5h. 50m. a.m., 
or 1h. 8m. before the Sun, with a southern declination of 
8° 53’, and an apparent diameter of 8?', rather over ;1,th 
of the dise being illuminated. He is then some little 
distance to the N.E. of Spica Virginis. He is at his 
greatest eastern elongation (254°) on the 1st. 

Venus is a morning star, and is getting well placed for 
observation. On the 1st she rises at lh. 43m. a.m., or 
1h. 18m. before the Sun, with a southern declination of 
2° 10’, and an apparent diameter of 541”, ,°,ths of the 
disc being illuminated. On the 8th she rises at 4h. 
A.M., or two hours and a quarter before the Sun, with a 
southern declination of 0° 18’, and an apparent diameter 
of 503”, ;'j5ths of the disc being illuminated. On the 18th 
she rises at 8h. 19m. a.m., or 3h. 12m. before the Sun, 
with a northern declination of 1° 7’, and an apparent 
diameter of 43}”, ,2,ths of the disc being illuminated. On 
the 3lst she rises at 2h. 35m. a.m., or nearly four hours 
before the Sun, with a northern declination of 0° 48’, and 
an apparent diameter of 36”, .8,ths of the disc being 
illuminated. She is at her greatest brilliancy on the 26th. 
She describes a curiously looped path on the confines of 
Leo and Virgo during the month. 

Mars is in conjunction with the Sun on the 11th, and 
Saturn and Uranus are invisible. 

Vesta is an evening star, though her great southern 
declination militates against her successful observation. 
On the ist she souths at 9h. 29m. p.m., with a southern 
declination of 21° 52’. On the 12th she souths at 
8h. 40m. p.m., with a southern declination of 21° 35’. 
On the 81st she souths at 7h. 35m. p.m., with a southern 
declination of 20° 17’. During October she appears 
as a 7th magnitude star. A map of the small stars near 
her path will be found in the English Mechanic for August 
2nd. 

Jupiter is an evening star, rising on the Ist at 11h. 56m. 
p.M., with a northern declination of 19° 23’, and an 
apparent equatorial diameter of 385-7"; the phase 
amounting to }’. On the 7th he rises at 11h. 88m. 
P.M., with a northern declination of 19° 18’, and an 
apparent equatorial diameter of 364”. On the 17th he 
rises at 1lh. 5m. p.m., with a northern declination of 
18° 56’, and an apparent equatorial diameter of 871”. On 
the 81st he rises at 10h. 18m. p.m., with a northern 
declination of 18° 38’, and an apparent equatorial diameter 
of 383". During the month he describes a direct path in 


Cancer, being near 3 Cancri at the end of October. The 
following phenomena of the satellites occur while the 
planet is more than 8° above and the Sun 8° below the 
horizon. On the Ist a transit egress of the first satellite 
at lh. 46m. a.m. On the 4th a transit ingress of the 
shadow of the fourth satellite at 4h. 28m. a.m. On the 
7th an eclipse disappearance of the third satellite at 
Oh. 44m. 7s. a.m.; a transit ingress of the shadow of the 
second satellite at 2h. 10m. a.m.; an eclipse disappearance 
of the first satellite at 2h. 59m. 52s. a.m.; an eclipse 
reappearance of the third satellite at 4h. 5m. 6s. a.m.; a 


| transit ingress of the second satellite at 4h. 57m. a.m. ; 


| a transit egress of its shadow at 5h. 1m. a.m. 


On the 8th 


| a transit ingress of the first satellite at 1h. 23m. a.m.; a 


{ 





transit egress of its shadow at 2h. 30m. a.m.; a transit 
egress of the satellite itself at 8h. 43m. a.m. On the 
9th an occultation reappearance of the first satellite at 
Oh. 58m. a.m., and an occultation reappearance of the 
second satellite at2h. 8m. a.m. On the 13th an occultation 


the 14th an eclipse disappearance of the third satellite at 
4h. 41m. 53s. a.m.; a transit ingress of the shadow of the 
second satellite at 4h, 43m. a.m.; an eclipse disappearance 
of the first satellite at 4h. 52m. 57s. a.m. On the 15th a 
transit ingress of the shadow of the first satellite at 2h. 5m. 
A.M., a transit ingress of the satellite itself at 3h. 19m. 
A.M.; a transit egress of its shadow at 4h. 24m. a.m. On 
the 16th an occultation reappearance of the first satellite 
at 2h. 53m. a.m. ; an occultation reappearance of the second 
satellite at 4h. 49m. a.m. On the 18th a transit egress of 
the third satellite at 83h. 21m. a.m. On the 21st a transit 
egress of the shadow of the fourth satellite at 2h. 25m. a.m. 
On the 22nd a transit ingress of the shadow of the first 
satellite at 83h. 58m. a.m.; a transit ingress of the first 
satellite at 5h. 15m. a.m. On the 23rd an eclipse dis- 
appearance of the first satellite at lh. 14m. 163. a.m. ; an 
eclipse disappearance of the second satellite at 1h. 59m. 46s. 
A.M.; an occultation reappearance of the first satellite 
at 4h. 48m. a.m. On the 24th a transit egress of the 
shadow of the first satellite at Oh. 46m. a.m.; a transit 
egress of the first satellite at 2h. 3m. a.m. On the 25th a 
transit egress of the second satellite at 2h. 4m. a.m.; a 
transit egress of the shadow of the third satellite at 
2h. 11m. a.m.; a transit ingress of the third satellite at 
8h. 47m. a.m. On the 29th a transit ingress of the shadow 
of the first satellite at 5h. 52m. a.m. On the 30th an 
occultation reappearance of the fourth satellite at Oh. 24m. 
A.M.; an eclipse disappearance of the first satellite at 
83h. 7m. 19s. a.m.; an eclipse disappearance of the second 
satellite at 4h. 85m. 58s. am. On the 31st a transit 
ingress of the shadow of the first satellite at Oh. 21m. a.m., 
a transit ingress of the satellite itself at lh. 87m. am., a 
transit egress of its shadow at 2h. 40m. a.m., and a transit 
egress of the first satellite at 3h. 57m. a.m. 

Neptune is an evening star, and is now well situated 
for observation. He rises on the 1st at Sh. 22m. p.m., 
with a northern declination of 21° 28’, and an apparent 
diameter of 2°6’’. On the 31st he rises at 6h. 23m. P.., 
with a northern declination of 21° 24’. During the month 
he describes a short retrograde path to the 8.8.W. of the 
63 magnitude star 108 Tauri. A map of the small stars 
near his path is given in the K’nglish Mechanic for August 
16th. 

October is rather a favourable month for observations 
of shooting stars, the most marked shower being that of 
the Orionids, from the 17th to the 20th of the month, the 
radiant being situated in R.A. VI[h. Om. +15° declination. 
The radiant point rises about 8h. 45m. p.m., and sets 
shortly after 4h. a.m. 


AVE 








XUM 








OctoseR 1, 1895.} 


KNOWLEDGE. 








The Moon is full (‘‘ Harvest Moon”’) at 10h. 47m. p.m. 
on the 3rd; enters her last quarter at 2h. 34m. p.m. on 
the 11th; is new at 6h. 10m. a.m. on the 18th; and enters 
her first quarter at 11h. 4m. a.m. on the 25th. She is in 
apogee at 2h. a.m. on the 25th (distance from the earth 
252,000 miles), and in perigee at 5h. p.m. on the 16th 
(distance from the earth 224,320 miles); and in apogee 
again at 4h. p.m. on the 28th (distance from the earth 
251,650 miles). 








Chess Column. 
By C. D. Lococx, B.A.Oxon. 





Communications for this column should be addressed to 
C. D. Lococx, Burwash, Sussex, and posted on or before 
the 12th of each month. 

Solutions of September Problems, 
(A. C. Challenger.) 
No; 1. 
1. Kt to QR5, and mates next move. 
No. 2. 
Key-move.—1. K to B7. 
lfl....KtoK4, 2. P to K8, ete. 
1....KtoK6, 2. B to Ktdch, ete. 

Correct Soxtvutions of both problems received from 
Alpha, E. W. Brook, W. Willby, A. Louis, G. A. F., 
J. T. Blakemore. 

Of No. 1 only, from H. 8S. Brandreth, G. G. Beazley, and 
A. E. Whitehouse. 

J. T. Blakemore.-—Your other three-mover has a rather 


pretty second solution beginning with 1. B to Bdch. 
In correcting it could you not contrive to employ a smaller 





force? ‘Twenty-six pieces are rather more than most 
solvers care to see. Your other problem (amended) appears 
below. 
PROBLEM. 
By J. T. Buakemore. 
Brack (6). 








ZA ‘sa a 


—s 














aie 
see 


White mates in nies moves. 














The game given below was played in the fourteenth 
round of the Hastings International Tournament. 


‘¢ Evans Gambit.” 


WHITE. BLack. 
H. E. Bird. H. N. Pillsbury. 
1. P to K4 1. Pto K4 
2. Kt to KB38 2. Kt to QB38 
8. B to B4 8. B to B4 











239 

4. P to QKt4 4, Bx KtP 

5. P to B38 5. B to Q3 (a) 

6. P to Q4 6. Kt to B38 

7. Kt to Kt5 (b) 7. Castles 

8. Ktx KBP (c) 8. Rx Kt 

9. Bx Reh 9. KxB 
10. P to KB4 10. Px QP (d) 
11. P to K5 11. B to K2 
12. Px Kt 12. BxP 

13. Castles 18. P to Q4 
14. Kt to Q2 (e) 14, PxP 
15. Kt to B83 15. K to Ktl (/) 
16. R to Ktl 16. P to QKt3 
17. B to K8 (y) 17. B to Kt5 (h) 
18. Q to R4 18. Bx Kt 
19. RxB 19. Q to Q3 
20. R to Q1 20. R to Ql 
21. R to RB (7) 21. P to Q5 
22. B to B1 22. Q to K3! 
23. Q to B2 23. P to Q6 (/) 
24. R (R3) x QP 24. Kt to Q5 
25. P to B5 (/) 25. Q to K5 
26. B to R3 26. P to B4 (I) 
27. Q to KB2 27. Kt to K7ch 
28. K to Bl 28. RxR 
29. RxR 29. QxR 
30. Q x Kt 80. Q x Pech 
81. K to K1 31. Q to Kt8ch 
82. K to B2 32. B to Qdch 
33. K to Kt3 33. Q to Kt3ch 
34. K to R38 34. P to KR4 
35. P to Kt3 35. Q to Ktdch 
36. QxQ 36. Px Qch 
a; RET 37. B to K6 
38. K to B38 38. B to R38 


39. Resigns. 
Noves. 

(a) Commonly regarded as inferior; but Mr. Pillsbury 
believes in it, and adopted it consistently throughout the 
tournament. 

(b) The beginning of an ingenious but not very advan- 
tageous combination. The ‘‘ Handbuch’’ recommends 
7. Castles, Ktx KP? 8. PxP, with the advantage. 


(c) A game between Anderssen and Kieseritzky was 
continued 8. P to B4, Px BP; 9. P to K5, BxP; 10 
PxB, KtxP; 11. B to Kt8, P to KR3, and Black has 
more than an equivalent for the piece. 

(d) The correct reply. If instead he play 10... 
B to K2, 11. BP x P, Kt to Ksq; 12. Q to Kt8ch wins for 
White. So also 10. ...KtxKP, 11. BPxP, Q to 
Rdch; 12. P to Kt3, Ktx KtP; 13. Q to B8ch, Kt to 
B4ch ; 14. K to Qsq is good for White. 

(e) A mistake ; he should defend the Pawn at all hazards 
by 14. B to Kt2. 

(f) Threatening P to B7, which he cannot play at once 
on account of 16. QxP! BxR;17. Kt to Ktdch, with a 
winning attack. 

(vy) Tempting Black to play 17... . P to Q5, which 
would be premature. The Queen might check in reply, 
followed by 19. R to Qsq. 

(hk) Or 17. ...B to B4, 18. R to Kt5, Kt to K2; 
19. B to Q4 (or Kt to Q4), P to B4, ete. 

(‘) B to Bsq at once would save a move. 


(j) This may possibly be an oversight. Though Black 
wins, the complications are so bewildering that a player in 








240 KNOWLEDGE. 


[Octoser 1, 1895. 








Black’s position should hardly have ventured on incurring 
the risk. 

(k) Just to make it more complicated, but it only 
improves Black’s position. He should play Q to KB2 at 
once. 

(l) Obviously, if he takes the Queen, White mates in 
four moves; but the trap was worse than useless, and 
enabled the American champion to finish off the game with 
a few powerful strokes. 


The Chess Openings. By I. Gunsberg. (George Bell 
and Sons.) This is certainly one of the most useful of the 
many shilling guides to the openings which have appeared 
during the last few years. The leading idea of each 
opening is explained before it is analysed, while the analysis 
itself is select rather than exhaustive. Indeed, some 
openings—notably the French defence, which is rather 
peremptorily dismissed in four columns—might well have 
received a more discursive treatment. Others, such as the 
close game, occupy more space than usual. The tables 
are brought well up to date, and in many cases are original, 
old-fashioned variations being discarded in favour of the 
new. The book gains additional value from the fact that 
it is the work of a recognized expert. 


Common Sense in Chess. By Emanuel Lasker. Mr. 
Lasker informs us that his recent series of twelve lectures 
on the game will shortly be published under the above 
title. Single copies will be sold at 2s. 6d., but a con- 
siderable reduction will be given on orders for six copies 
or more. Subscriptions tor the work should be sent to 
E. Lasker, 71, Chiswell Street, London, E.C. 





CHESS INTELLIGENCE. 


After more than four weeks’ continuous play, the 
International Tournament at Hastings was brought to a 
successful conclusion on September 3rd. The following is 
the complete score :— 

Ist prize (£150) - H.N. Pillsbury - 163 


2nd prize (£115) - M.Tchigorin - - 16° 
8rd prize (£85) - KE. Lasker - - - 154 
4th prize (£60) - Dr. 8. Tarrasch - 14 
5th prize (£40) - W.Steinitz- - - 18 
6th prize (£30) - E.Schiffers- - - 12 


ss . C. Von Bardeleben ) 
ith prize (£20) - i ack mane 114 

The remainder in order being :—C. Schlechter, 11; J. H. 

Blackburne, 10} ; C. Walbrodt, 10; A. Burn, D. Janowski 

and J. Mason, 94; H. KE. Bird and I. Gunsberg, 9; A. 

Albin and G. Marco, 8}; W. H. K. Pollock, 8; J. Mieses 

and §. Tinsley, 74; and B. Vergani, 3. 

Mr. Pillsbury’s victory comes as a surprise even to those 
who knew of the improvement in his play. The young 
Bostoniaii is not yet twenty-three, and this is his first 
International Tournament. He and Tchigorin owe their 
position to their escape from any continuous run of ill-luck 
such as befell Tarrasch in the first week, Steinitz in the 
second, and Lasker in the third. On the other hand, 
Pillsbury refused a draw with Schlechter, and had 
considerably the best of his drawn game with Marco. 
Lasker played finely, apart from the temporary breakdown 
referred to, and some of his victories were the shortest 
games of the tournament. Tarrasch and Steinitz recovered 
lost ground in a marvellous manner during the concluding 
stages ; given perfect health, all these three might have 
been at the top. The same cause spoilt Von Bardeleben’s 
chances. For the first fortnight he was invincible ; after 
that he broke down, and had to resign a game to Pillsbury 





without playing. Schlechter gave up his drawing policy 
in the last week or so; still he drew no less than twelve 
games out of the twenty-one played. Many will be 
surprised at Bird drawing ten games, but here the cause is 
different. Violent attacks lead to open positions in which 
both Kings are liable to perpetual check ; moreover, Mr. 
Bird draws many end-games which with more accurate 
play might be won. Of the other players, Walbrodt and 
Marco lost far more games than they are accustomed to 
lose. Marco’s score is particularly disappointing; in 
Vienna he is considered superior to Schlecter. Mieses 
secured some good draws against the strongest players ; 
otherwise he hardly did himself justice after the first week. 
Those who noticed our prediction in the August number— 
that the first prize winner would score 16, and the last on 
the list but one, 7—will see how nearly it was verified, 
both scores being correct within half a point. The Italian 
representative, as we expected, had no rival to dispute his 
claim to the last place. Pollock did very well in beating 
Steinitz and Tarrasch, and so coming out above Mieses. 

The Minor Tournament must be dismissed briefly. 
There were thirty-two entries, and the prizes were taken 
as follows :—1, Herr Geza Maroczy; 2, R. Loman and 
H. E. Atkins; 4, Herr W. Cohn. These were the four 
section winners. Messrs. F’. Hollins, R. P. Michell, Dr. 
Smith, and Rev. J. Owen were second in their sections, 
and took the lesser prizes in the order mentioned. Mr. 
Owen actually tied with Herr Maroczy in his section, but 
lost in playing off, and afterwards brokedown. Mr. Atkins 
takes the challenge cup, and the title of Amateur Champion 
of Great Britain. 


Contents oF No. 119. 
PAGE | PAGE 
The International Geographical Blind Cave-Animals. By ; 
Congress in London................... 193 Lydekker, B.A.Cantab., F.R.S. 
The Newly-Found Race in Egypt. (Illustrated) os saheres 
By J. E. Quibell. (Illustrated) 196 
Wind-Fertilized Flowers. By the 


2(8 


Helium, together with a Few 
Notes on Argon. By George 


Rev. Alex. S. Wilson, M.A., McGowan, Ph.D... . 210 
B.Sc. (Illustrated) ...............« 199 - ‘ahh hadi 
Notices of Books ..c.....escee--2-, 202 The Coldest Tnhabited Spots on 
ee Earth. By Carl  Siewers. 
FOGMORNSD DROOL caavcissecatesyasinassnenss 204 (IUlustvated) : . were 213 


Letters :—(Rev.) Pat. Stevenson ; 
Wm. Miller; E. M. Antoniadi 
(IUustrated) pédaevohuewatbiauene dea 

Satellite Evolution. By Miss A. 


Some Recent Patents (Illustrated) 215 


The Face of the Sky for Sep- 
tember. By Herbert Sadler, 
BAe: sccccsseess. 0 eens eee 


204 


BR ERS: vaca gs cestcasns : .. 205 24 
Photographs of Elliptical and 

Spiral Nebule. By Isaac Chess Column, By C. D. Locock, 

Roberts, D.Sce., F.R.S.......... BOE 1 RRS pees csncasesscteretccsoseses 215 
Two Priates.—l, Sketch Map of the World; 2, Photographs of Elliptical 


and Spiral Nebule. 


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