162 Scientific Intelligence. 
eine at each. The fact that much of the matter has either not 
been published before, or, if at all, in periodicals not generally 
accessible, makes the book a valuable one to all interested in min- 
meaty and gives it more than a local interest 
6. Zoology for High Schools and wpe the ‘by A.S, PackarD, 
ne Second edition, revised. New Yo Henry Holt & Co. 
1880.—In this edition, many improvements have been intro- 
duced, and some errors contained in the first edition have been 
corrected. e pete asap figures of the brains of fishes 
On 
ss upotiests i the former fluidity of the aa, BY Professor 
Hennessy, (C. Rend., June, 1880).—Professor Hennessy here 
gives a calculation of the polar depression in Mars, supposing it to 
have been a result of rotation during a condition of fluidity. As- 
suming that the mass is distributed in spheroids of equal density, 
the density increasing from the surface to the center, and that the 
ellipticity depends on this law and the period of rotation of the 
planet, he arrives at the value 
: ee. 
227°61 
which he says’ is very near the peste oo in the careful 
observations of Professor C. A. Young,* namely, 
1 
ea 
9 
Professor Pir iecope also calculates the polar depression sUp- 
posing it t a result of erosion by a liquid moving over t the 
surface of the plaicet, ca obtains 
piu 1 
~ 179°24" 
which he observes is — larger than the results of the best 
measurements, e states, therefore, that Young’s result much 
better accords with the hypothesis of the former fluidity of the 
planet than with that of a shaping by erosion; and that this corre 
sponds with the parallel fact as regards the eart 
* This Journal, xviii, 206, March, 1880. 
