By Josiah P. Cooke, Jr., Erving Professor of Chemistry and Mineralogy in Harvard University.

I vol.,12mo. Cloth............Price, $2.00.

"The book of Prof. Cooke is a model of the modern popular science work. It has just the due proportion of fact, philosophy, and true romance, to make it a fascinating companion, either for the voyage or the study." - Daily Graphic.

"This admirable monograph, by the distinguished Erving Professor of Chemistry in Harvard University, is the first American contribution to 'The International Scientific Series,' and a more attractive piece of work in the way of popular exposition upon a difficult subject has not appeared in a long time. It not only well sustains the character of the volumes with which it is associated, but its reproduction in European countries will be an honor to American science." - New York Tribune.

"All the chemists in the country will enjoy its perusal, and many will seize upon it as a thing longed for. For, to those advanced students who have kept well abreast of the chemical tide, it offers a calm philosophy. To those others, youngest of the class, who have emerged from the schools since new methods have prevailed, it presents a generalization, drawing to its use all the data, the relations of which the newly-fledged fact-seeker may but dimly perceive without its aid. To the old chemists, Prof. Cooke's treatise is like a message from beyond the mountain. They have heard of changes in the science; the clash of the battle of old and new theories has stirred them from afar. The tidings, too, had come that the old had given way; and little more than this they knew. Prof. Cooke's' New Chemistry' must do wide service in bringing to close sight the little known and the longed for. As a philosophy it is elemen-tary, but, as a book of science, ordinary readers will find it sufficiently advanced." Utica Morning Herald.

D. Appleton & CO., Publishers, 549 & 551 Broadway, N. Y.

Opinions of the Press on the "International Scientific Series"