BY E. L. YOUMANS.

12mo. 340 pages. Price 75 cents.

Every page of this book bears evidence of the author's superior ability of perfectly conforming his style to the capacity of youth. This is a merit rarely possessed by the authors of scientific school-books, and will be appreciated by every discriminating teacher. While Chemistry is almost universally regarded by students as a dry and repulsive study (owing to the rigid and technical manner in which it is presented), Mr. Youmans' work will be found pre-eminent in clearness and simplicity of diction, by which the subject is made at once interesting and attractive. It is especially commended by the eminently practical manner in which each subject is presented. Its illustrations are drawn largely from the phenomena of daily experience, and the interest of the pupil is speedily awakened by the consideration that Chemistry is not a matter belonging exclusively to physicians and professors.

From Prof. Wm. H. Bigelow.

The eminently practical character of the Class-book, treating of the familiar applications of the science, is, in my opinion, its chief excellence, and gives it a value far superior to any other work now before the public.

From David Syme, A. M., formerly Principal of the Math. Dept. and Lecturer in Nat. Philosophy, Chemistry, and Physiology, in Columbia College.

Mr. Youmans: Dear Sir,—I have carefully examined your Class-Book on Chemistry, and, in my opinion, it is better adapted for use in schools and academies than any other work on the subject that has fallen under my observation.

I hope that the success of your Class-Book will be proportionate to its merits, and that your efforts to diffuse the knowledge of Chemistry will be duly appreciated by the friends of education.

From Prof. J. Mulligan, Principal of Young Ladies' School, New York.

We have a large number of school-books for the purpose of giving elementary instruction in Chemistry—possessing various kinds and various degrees of merit; but of all which I have examined, I should prefer the Class-Book of Chemistry, as the most perspicuous in style and method, and as containing the happiest selection of what is most interesting, and most practically valuable in the vast field of chemical science.

From the N. Y. Commercial Advertiser.

Either for schools or for general reading, we know of no elementary work on Chemistry which in every respect pleases us so much as this.

From the Scientific American.

Such a book, in the present state of chemical science, was demanded; but to present the subject in such a clear, comprehensive manner, in a work of the size before us, is more than we expected.

The author has happily succeeded in clothing his ideas in plain language—true eloquence—so as to render the subject both interesting and easily comprehended. The number of men who can write on science and write clearly, is small; but our author is among that number.

Chemical Chart:

BY E. L. YOUMANS.

On Rollers, 5 feet by 6 in size. New Edition. Price $5.

This popular work accomplishes for the first time, for Chemistry, what maps and charts have for geography, geology, and astronomy, by presenting a new and valuable mode of illustration. Its plan is to represent chemical composition to the eye by colored diagrams, so that numerous facts of proportion, structure, and relation, which are the most difficult in the science, are presented to the mind through the medium of the eye, and may thus be easily acquired and long retained. The want of such a chart has long been felt by the thoughtful teacher, and no other scientific publication that has ever emanated from the American press has met with the universal favor that has been accorded to this Chart. In the language of a distinguished chemist, "Its appearance marks an era in the progress of the popularization of Chemistry."

It illustrates the nature of elements, compounds, affinity, definite and multiple proportions, acids, bases, salts, the salt-radical theory, double decomposition, deoxidation, combustion and illumination, isomerism, compound radicals, and the composition of the proximate principles of food. It covers the whole field of Agricultural Chemistry, and is invaluable as an aid to public lecturers, to teachers in class-room recitation, and for reference in the family. The mode of using it is explained in the class-book.

From the late Horace Mann, President of Antioch College.

I think Mr. Youmans is entitled to great credit for the preparation of his Chart, because its use will not only facilitate acquisition, but, what is of far greater importance, will increase the exactness and precision of the student's elementary ideas.

From Dr. John W. Draper, Professor of Chemistry in the University of N.Y.

Mr. Youmans' Chart seems to me well adapted to communicate to beginners a knowledge of the definite combinations of chemical substances, and as a preliminary to the use of symbols, to aid them very much in the recollection of the examples it contains. It deserves to be introduced into the schools.

From James B. Rogers, Professor of Chemistry in the University of Pennsylvania.

We cordially subscribe to the opinion of Professor Draper concerning the value to beginners of Mr. Youmans' Chemical Chart.

JOHN TORREY,
Professor of Chemistry in the College of Physicians & Surgeons, N.Y.

WM. H. ELLET,
Late Professor of Chemistry in Columbia College, S.C.

JAMES B. ROGERS,
Professor of Chemistry in the University of Pennsylvania.

From Benjamin Silliman, LL. D., Professor of Chemistry in Yale College.

I have hastily examined Mr. Youmans' New Chemical Diagrams or Chart of chemical combinations by the union of the elements in atomic proportions. The design appears to be an excellent one.