310 
We TORE 
[ Feb. 1, 1883 
witnessed by many observers prove the existence of 
elevations much more considerable than any upon the 
earth: as to Mercury, notwithstanding Schréter’s de- 
ficiency as an artist, and his occasional mistakes of pre- 
conception, his observations are always too honest and 
faithful to be set wholly aside ; and we are not sure that 
the uselessness of devoting time to this planet may not 
be found a mistake at some future day. 
As to the physical condition of Mars, we venture to 
think that our author has dealt very fairly and judiciously 
with a subject of controversy, which might have become 
less pleasant but for the unassuming modesty of Schia- 
parelli and the liberal candour of Green, so honourable to 
each of them. We are not sure that it is always borne in 
mind, how much of the difference may have been due to 
the early return of the English observer from Madeira to 
a far inferior climate, previous to the development of the 
additional features which were subsequently perceived at 
Milan, and which may possibly, like their strange gemina- 
tion, become more visible from prolonged solar influence, 
The less favourable position of the planet at the next 
opposition is much to be regretted; but Schiaparelli’s 
experience has warned us that increase of distance may 
possibly be compensated by improvement in definition : 
to which we would add on the one hand the constantly 
verified adage of Sir W. Herschel, that “ when an object 
is once discovered by a superior power, an inferior one 
will suffice to see it afterwards” ; and on the other, the 
advantage which may be expected from the 18 inches of 
aperture with which the Italian Government are about to 
mark their appreciation of their astronomer’s ability, and 
their willingness to enable him to meet the emergency. 
It will be matter of regret, if in this honourable contest no 
corresponding preparation should be made among our- 
selves; though it is difficult indeed to counteract the 
disadvantage of the English sky. It is not easy to forecast 
the result ; but we think there are indications that possibly 
the supposed terrestrial analogy has been pushed quite 
far enough. As to the interesting question of the habita- 
bility of Mars by beings like ourselves, it deserves more 
attention than it perhaps has often received, that none of 
.the supposed correspondence with our own constitution 
could be maintained excepting on the supposition of a 
higher internal temperature on the, globe of Mars, or pos- 
sibly a very different composition of atmosphere. We 
are not so much struck as the author with the progressive 
diminution of the measured diameter of Mars effected by 
the employment of modern instruments; at least Schroter’s 
determination by the mode of projection in 1798 scarcely 
exceeds by 05 that adopted by Newcomb for 1850. 
Irradiation no doubt is a fact; and a very troublesome 
one; but we suspect that its effects have been sometimes 
over-estimated, or mixed up with those of diffraction ; 
and possibly the subject might bear further investigation. 
As to the internal heat of Jupiter, so interesting an 
inquiry ought not to have been left so long in abeyance. 
If it exists, it would hardly be less capable of detection 
than that of Arcturus; and the bolometer of Langley 
seems to offer a fair chance for the discovery. The satel- 
lite whose strange reappearance is so difficult of explana- 
tion was, it will be found, about to enter on transit instead 
of suffering occultation. It may be noted, ex passant, 
that a telescope must have had a marvellous power of 
indistinctness, that could show M. Flammarion the third 
satellite with a disc as large as that of Uranus (p. 409). 
It seems a pity that the traditional misrepresentation 
of the ball of Saturn, at p. 358, as carrying a faint shadow 
on one side, should still be adhered to; and we may 
venture to suggest that there is a good deal of inequality 
in the execution of the diagrams in various parts of the 
book. 
We are confident that the author will not misunder- 
stand our remarks, or hesitate to accept our assurances 
that they are made in the most friendly spirit. If we 
are in error, he is fully able to hold his own; and he 
has our cordial wishes not only for his success on the 
present occasion, but for the extension of his labours, at 
no distant time, to a wider review of the glorious works 
of Nature. 
THE ZOOLOGICAL RECORD 
The Zoological Record for 1881. Being Vol. xviii. of the 
“Record of Zoological Literature.” Edited by E. C. 
Rye. (London : John Van Voorst, 1882.) 
T is gratifying to be able to announce that the perse- 
vering efforts of the editor of the Zoological Record 
to publish the record of one year’s work before the ter- 
mination of the next year have been at last crowned with 
success ; nor do we doubt but that this very desirable 
effort will be continued, and indeed become even less 
difficult with the advance of time, so that through the 
good will of the Recorders the date of publication will 
recede backwards from December to September or August 
in each year, enabling the worker to begin his autumn 
session with the volume in his hand. The facilities of 
intercourse are now so great with all parts of the world, 
that the Transactions and Proceedings really published 
in the month of December in any one year can be, nay 
are on our bookshelves in these British Isles, long ere 
the spring is on its wane, and no doubt long ere 1882 
was out, some of the Recorders of this very volume had 
the record for that year well in hand. However grea 
may be our expectations for the future we cordially wel- 
come this present volume, and acknowledge that our 
thanks are due to both Editor and Recorders for what they 
have already done. 
To those who have time for reflection and dare to look 
back over those eighteen years since Dr. Giinther and his 
friends launched this work upon the world of science, the 
thought naturally arises of the vastness of the amount of 
work that is year after year being accomplished without 
apparertly in any way leading to exhaustion. The Editor’s 
own comments are naturally in the volume very few, but 
how full of meaning is the following: “This volume is 
36 pages longer than its predecessor,” that is, even the 
very enumeration of the zoological literature of 1881 re- 
quires about 800 closely printed pages ; and again we 
read, “the number of new genera and sub-genera con- 
tained in the present volume is 1438”—a simply appalling 
number. The Insecta are credited with 543, and the Pro- 
tozoa with 517 of these genera. An enthusiastic zoologist 
once contemplated the posting up to date of Agassiz’s 
“ Nomenclator Zoologicus,’’ that was when the generic 
increase was some 400 to 500 a year; what would he 
