602 
which is not yet sufficiently rigid to resist. The result is 
that phenomena resembling lunar craters are produced. 
These craters, therefore, are not the result of ejections 
resembling volcanic eruptions from within, but are the 
results of action from without. Further than this, the 
matter carried into the body of the moon will in its 
turn be melted in the heated interior; consequently 
the thin crust will no longer be able to support the 
internal pressure, and rents or fissures of the hardened 
exterior will take place, and this is the cause of 
the bright streaks or radiations which can readily 
be seen on the most superficial examination of the moon. 
It might be urged in opposition to this view that the 
molten matter ejected from the interior must soon cool, 
and not only destroy the traces of the meteoric bombard- 
ment, but would also thicken the crust and tend to 
prevent the penetration of fresh meteors. If one asks 
why the earth or Mars does not show similar signs of 
precipitated matter, Dr. Meyer is ready with his 
answer. By the time that the greater mass of a planet 
had sufficiently cooled, all the larger débris, the results 
of the original collision, had been absorbed, and the 
smaller masses either fell upon the stiffening crust with- 
out penetrating it, or were volatilised by friction with the 
atmosphere, which in those days, it is suggested, was 
more dense than at present. And if anyone, still un- 
convinced, asks how it is that Jupiter, for example, can 
drink up all the matter in a cosmical ring extending into 
indefinite space, and yet refuses to swallow the small 
mouthful which in the form of the fifth satellite tanta- 
lisingly tempts its capacious appetite, the answer is, wait. 
All the satellites will eventually be drawn in and form 
an integral portion of their respective primaries, just as 
these in their turn will be absorbed in the sun, to be 
followed again at immense intervals of time by the 
crashing together of defunct suns producing a larger 
set of planets with a larger and hotter sun, a solar 
system on a vaster scale than that in which we play our 
little part. And so growing in grandeur but diminishing 
in number, the final catastrophe will come, when there 
are no more suns to produce collisions, and one huge 
body cooled to the zero of space, void of available energy, 
will mark the final outcome of cosmical motion. 
This, if we understand our author, is the final state of 
rest, but there are qualifications introduced which may 
modify this conclusion. We have endeavoured to draw 
the conclusion without entering into the limitations which 
depend, more or less, “in unsern unvollendeten Geist.” 
The only objection one might urge is to the insistence on 
the lowering of the temperature of the mass to that of the 
absolute zero. It is only necessary for a uniform tem- 
perature, however great, to exist throughout the whole, 
when a practically useless state of kinetic energy would 
result, and no work would be possible. 
On this world, however formed, it is necessary to in- 
troduce life, and, if possible, without a definite creative 
act implying a breach of continuity. Dr. Meyer follows, 
but without acknowledgment so far as we have seen, the 
hypothesis of Helmholtz or of Kelvin. We imagine that 
the author regards life as old as matter itself, and that 
its transition from a defunct world to a new one is effected 
by means of germs, borne through space on fragments ; or 
so-called meteors, and whenever’ such germs meet with 
NO. 1720, VOL. 66] 
NATURE 
[OcTOBER 16, 1902 
a favourable environment the processes of life are con- 
tinued. Ina collision, heat would be generated only in 
proportion as motion is destroyed, so that, as the author 
is careful to point out, fragments could escape without 
any great development of heat or necessary destruction 
of all forms of life. But we do not understand so clearly 
his theory of the method by which the meteoric frag- 
ment, carrying life to a new world, finds itself 
deposited there. But this is of little conse- 
quence, since meteors do come here, and if their 
surface is heated by friction, the interior can be of lower 
temperature. Or it can very well happen that germs 
lying on the surface would be blown away in the highest 
and most attenuated strata of the earth’s atmosphere 
before the fragment reached the denser parts of the 
gaseous mass, where the compression becomes great 
enough to generate considerable heat. The author, 
however, seems to think it necessary to give to the 
meteor the same velocity as that of the earth, so that it 
is quietly and gently deposited on the surface without 
any arrest of motion and therefore without any increase 
of temperature. Indeed, he seems to think that meteors, 
bringing with them enormous masses of water, can 
accompany the earth for some days in its journey round 
the sun, giving rise to severe local storms, and marvels 
that meteorologists have not entertained such explana- 
tions as legitimate and worthy of consideration. It is 
true that the author does not say that these meteors are 
moving in a circular orbit, but he allows this to be in- 
ferred, since parabolic velocities do not seem to be con- 
sidered. We gather from an account that the author 
gives of a controversy with Dr. Palisa that that astro- 
nomer has had some difficulty in following Dr. Meyer’s 
views, and, so far as we can follow the account from the 
description of one of the disputants, we would re- 
spectfully associate ourselves with the opinion of Dr. 
Palisa. 
We have dwelt, perhaps, at too great length on the 
points of difference that separate us from the author, and 
have no space to enter on other matters, which we would 
do the more willingly since no note of disapprobation 
need accompany our remarks. In many respects, the 
book is very interesting, and many chapters can be read 
with equal pleasure and profit, though ‘the connection 
with terrestrial catastrophes is not very apparent. Dr. 
Meyer has selected a subject of great interest, but one on 
which diverse views can be maintained more or less 
legitimately. He can write pleasantly and clearly, and 
while his book may be instructive to the general reader, 
for he studiously avoids all technical expressions, it 
should not be offensive to the most orthodox theologian. 
ARTIFICIAL MINERAL WATERS. 
The Evolution of Artificial Mineral Waters. By 
William Kirkby, F.L.S. Pp. x + 155. (Manchester : 
Jewsbury and Brown, 1902.) Price 3s. 6d. 
HIS little book has been written with the object of 
showing the origin and development of the mineral 
water industry, an industry the commercial importance 
of which may be to some extent gauged by the author’s 
statement that our annual exports amount to more than 
es 
