Opinions of the Press on the “International Scientific Series.” 
XIII. 
THE DOCTRINE OF 
Descent, and Darwinism. 
By OSCAR SCHMIDT, 
Professor in the University of Strasburg. 
Witn 26 Wooncuts. 
1 vol.,12mo. Cloth, . .. .. . . « Price, $1.50. 
“The entire subject is di: d with a fresh as well as an elaboration of de- 
tail, that renders his work interesting in a more than usual degree. The facts upon 
which the Darwinian theory is based are presented in an effective manner, conclusions 
are ably defended, and the question is d in more p and ilable style 
than in any other work on the same topic that has yet app d. Itis a valuable ad- 
dition to the ‘ International Scientific Series,’ "—Boston Post. 
“ The p vol is the thi h of the ‘International Scientific Series,’ and 
is one of the most interesting of all of them. The subject-matter is handled with a 
great deal of skill and earnestness, and the courage of the author in avowing his opin- 
Ions is much to his credit. . . . This volume certainly merits a careful perusal.”"— 
Hartford Evening Post. 
«The volume which Prof. Schmidt has devoted to this theme is a valuable contri- 
bution to the Darwinian literature. Philosophical in method, and eminently candid, 
it shows not only the ground which Darwin had in his researches made, and conclu- 
sions reached before him to plant his theory upon, but shows, also, what that theory 
really is, a point upon which many good people who talk very earnestly about the 
matter are very imperfectly informed.” —Detroit Free Press. 
XIv. 
The Chemistry of Light and 
Photography ; 
In its Application to Art, Science, and Industry. 
By Dr. HERMANN VOGEL, 
Professor in the Royal Industrial Academy of Berlin. 
Wit 100 ILLUSTRATIONS. 
F2MO0s sw eee ce wee er ew ee Pri, $2.00, 
, ‘Out of Photography has sprung a new science—the Chemistry of Light—and, in 
giving a popular view to the one, Dr. Vogel has p d an analysis of the princip! 
and processes of the other. His treatise is as entertaining as it is instructive, pleas- 
antly combining a history of the progress and practice of photography—from the first 
rough experiments of Wedgwood and Davy with sensitized paper, in 1802, down to 
the latest improvements of the art—with technical illustrations of the scientific theories 
on which the art is based. It is the first attempt in any manual of photography to set 
forth adequately the just claims of the invention, both from an artistic and a scientific 
Point of view, and it must be conceded that the effort has been ably conducted.”— 
Chicago Tribune. > Ope al” 
D. APPLETON & CO., PUBLISHERS, 549 & 551 Broadway, N. Y. 
