POPULAR SCIENCE NEWS. 
[June, 1890. 
correspond with those observed at the moun- 
tain observatories of the Puy de Dome and 
Pic du Midi. A simihu" approximation to 
mountain stations is noticed in the tempera- 
ture, which averages from two to three degrees 
lower at the summit than at the base. A 
"cold wave" has also been known to pass 
over the observatory which did not aflect the 
temperature of the air in the city till a day or 
two later. 
While the actual elevation of the Eiflel 
observatory is small compared with that of 
many mountain stations, yet, as it stands by 
itself in the air, free from the influence of 
any surrounding objects, and in a position 
where the observations taken can be immedi- 
ately compared with those of an observatory 
in the same vicinity and at a lower level, it is 
particularly well adapted for investigations 
upon the influence of elevations upon mete- 
orological conditions ; and we may expect in 
the future a continuance of the valuable 
results already obtained. 
The accompanying illustration is repro- 
duced from La Nature. 
[Original in Popular Science Jftioe.] 
REVIEW OF MR. ALFRED RUSSEL WAL- 
LACE'S "DARWINISM." 
BY KATHARINE B. CLAYPOLE. 
There is a singular timeliness in the appearance, 
just now, of a volume that sets forth Darwinism in 
language so clear and a style so easy that any intel- 
ligent reader may obtain a correct insight into the 
power and range of the great principle. It is, 
moreover, peculiarly appropriate that such an expo- 
sition should come from the pen of Mr. Alfred 
Russel Wallace ; for it must never be forgotten that 
in the first publication of the theory, in the journal 
of the Linneau Society, July, 1858, the names of 
Darwin and Wallace stand side by side. To each 
had the formation of new species by means of the 
perpetuation by Nature of varieties best fitted to 
suivive in the struggle for existence, come as an 
original tliought. Into the mind of Darwin it had 
flashed, as far back as 1838, while patiently accumu- 
lating and reflecting on all sorts of facts bearing on 
the transmutation of species — that "mystery of 
mysteries" to which his attention had been directed 
during his recent voyage in the Beagle. To Mr. 
Wallace it occurred quite as independently, twenty 
years later, and afar oft' among the animals and 
plants of the Malay Archipelago. But, while the 
originality of the discovery belongs equally to Wal- 
lace and Darwin, as it was Darwin, through the 
twenty years of cogitation, investigation, experi- 
ment, and minute research, who was first able to 
command attention to the great principle, it became 
associated with his name alone, and for many years 
has been known as "Darwinism." If to the end of 
time it should not be so designated, it will not be 
the fault of Mr. Wallace, who, in his loyally to the 
memory of his friend, entirely suppresses himself, 
and speaks throughout his volume as though the 
theory of natural selection belonged to Darwin, 
and to Darwin alone. 
Darwinism, pure and simple, is the theme of Mr. 
Wallace's book, although, in the treatment of his 
subject, he by no means confines himself to an 
epitome of Darwin's work or to an exposition of 
Darwin's views. The years that have followed the 
publication of The Origin of Species have added 
immensely to our biological knowledge. Of the 
new facts thus brought out — many of which had 
been collected by Darwin for his own future use — 
Mr. Wallace avails himself largely, bringing some 
of them to bear critically even on the later work of 
the great master himself. 
After a brief statement of what naturalists have 
meant by the word species, and their origin, Mr. 
Wallace takes the reader, as it were, behind the 
scenes, and shows him Nature in anything but the 
calm, orderly, and peaceful state that sentimentalists 
like to picture. He shows organized life multiply- 
ing on all sides with fatal rapidity, and the few 
organisms that survive their earliest youth strug- 
gling one against another to secure the food and 
protection requisite to bring them to maturity. He 
points out the advantages possessed by those that 
are superior in the special qualities on which safety 
depends, and demonstrates the variety that may 
obtain in the nature and quantity of these qualities. 
That the reader should be convinced beyond doubt 
that Nature does seize upon and perpetuate any 
variation that gives its owner an advantage in the 
struggle for existence, it is of the utmost importance 
to firmly establish the principle that animals and 
plants do constantly vary in the manner and to the 
amount requisite to afford material on which natu- 
ral selection may work. Darwin, it will be remem- 
bered, appealed, for the most part, to the facts of 
variation among domesticated plants and animals, 
especially among dogs and pigeons. Mr. Wallace, 
making use of material that has only become acces- 
sible through the lines of research opened up by 
the work of Darwin, has found his wide and com- 
prehensive array of facts among animals and plants 
in a state of nature. So great, also, is the import- 
ance that he attaches to these facts, that he has, 
with rare ingenuity, prepared diagrams which ex- 
hibit variation in important organs as they are 
actually found among the members of many existing 
species. Indeed, so impressive is Mr. Wallace that 
the reader receives the conviction that, had he but I 
eyes to see it, he would discover, among the indl- I 
viduals of any species of animal or plant, as much 
variety in structure and habits as he finds among 
his human acquaintance. 
When it is remembered, moreover, that all the 
ofl'spring of any particular pair are subject to indi- 
vidualities, and that the few that survive to maturity 
are immensely outnumbered by the many that fall 
by the way, the number of variations constantly 
being produced in any large and widespread species 
is seen to be enormous, providing at all times some 
forms fitted to adapt themselves to a change in the 
natural conditions in which they were produced. 
Consequently, it is not difficult to follow Mr. Wal- 
lace in his most interesting summary of the present 
state of opinion on such oft-repeated objections to 
Darwin's theory as, the supposed smallness of vari- 
ations, the doubt as to the right variation occurring 
when required, the beginnings of important organs, 
useless or non-adaptive characters, the instability 
of non-adaptive characters, the swamping eft'ects of 
intercrossing, and the effects of isolation. In an 
equally interesting manner does he discuss the 
infertility of crosses between distinct species, and 
the usual sterility of their hybrid offspring. But 
even in his hands, and though he treats it at length 
and in a remarkably forcible manner, the subject 
will require the very closest attention on the part of 
anyone who wishes to gain a clear comprehension 
of all the arguments involved. 
The close correspondence that exists between the 
colors of animals as a whole and their general 
environment, has been made familiar of late bv 
means of many popular essays. The reader is, 
therefore, prepared to extend the principle of pro- 
tective resemblances to the colors of manv animals 
that appear glaringly conspicuous when removed 
from their. native haunts. It is not, at first, so easy 
to see that visibility may, in some cases, be of 
greater service than concealmiSnt. Nevertheless, 
Mr. Wallace's illustrations leave no room to doubt 
that to crepuscular animals, and to those that are 
more or less gregarious, it is of the utmost advan- 
tage that they should possess marks which render 
them easily distinguishable to their kind ; the white 
upturned tail of the rabbit, for instance, serving as 
a signal and guide to those behind in a panic- 
stricken race for the burrow. This class of colors 
— which he calls "recognition marks" — is believed 
by Mr. Wallace to have had an exceedingly import- 
ant and widespread influence in determining the 
diversities of animal coloration. It is not for recog- 
nition by friends alone, however, that color seems 
to have been developed for the express purpose 
of rendering a species conspicuous. To animals 
that are inedible, or possessed of dangerous, offen- 
sive weapons, it is a saving of energy, and even of 
life, to carry outward and visible signs of their 
character. These "danger-flag" colors Mr. Wal- 
lace shows to be especially displayed in the insect 
world, where, a wound inflicted by mistake bringing 
death as surely as if the victim were afterwards 
devoured by its assailant, there is great need of 
some well-defined markings or colors to make 
known to insectivores the species that it would be 
best for them to*void. Theassociated phenomenon 
of "mimicry" is treated by Mr. Wallace in a truly 
fascinating manner, and illustrated by wood cuts 
that clearly display the remarkable resemblances 
whereby many weak, small, edible species share the 
immunity from danger enjoyed by other species 
that are uneatable, dangerous, or merely strong. 
The differences of color or of ornamental append- 
ages in the two sexes is connected with some of the 
most disputed questions in natural history. Dar- 
win, as is well known, iitiputed the origin of all the 
decorative crests and accessory plumes of birds, the 
crests and beards of monkeys and other mammals, 
