REVIEWS 
Introduction | General Chemistry | an exposition of the principles of | modern 
Chemistry | by | H. Copaux | [two lines of titles] | translated by | 
Henry Leffmann, A.M., M.D. | [two lines of titles] | with 30 illustra- 
tions | Philadelphia | P. Blakiston’s Son & Co. | 1012 Walnut Street 
| Cloth, pp. i-x + 1-195 including index. Copyright, 1920. 
TRANSLATOR’S NOTE 
Professor Copaux’s work presents in compact, yet clear form 
a large amount of information on the principles of chemistry 
as recognized today by the leaders in the science. I have endeav- 
ored to render the text into standard English, and thus make 
it available to a wider group of readers, to whom it will be a 
Valuable guide. 
Those who, like myself, began the study of chemistry just 
after the middle of the last century, will find many points of 
difference between this book and the manuals of the early days, 
yet the fundamental features, of the science remain unchanged. 
The atom is still the unit of chemical action, and the balance is 
still, as in the laboratory of Lavoisier, the chemist’s, main 
reliance. 
While the translation was in progress, Professor Copaux 
kindly sent a copy of the book with notes of corrections of a few 
typographic errors, and some changes in phraseology adding to 
the explicitness or comprehensiveness, of the text. These 
suggestions have been given attention. 
French-English | Medical Dictionary | by | Alfred Gordon, A. M., M. D. 
(Paris) | [seven lines of titles] | Philadelphia | P. Blakiston’s Son & 
Co. ] 1012 Walnut Street | Cloth, $3.50 net, pp. 1-161. Copyright, 
1921. 
Priestley ] in | America | 1794-1804 | by | Edgar F. Smith | University of 
Pennsylvania | Philadelphia | P. Blakiston’s Son & Co. | 1012 Walnut 
Street | Cloth, $2 net, pp. 1-173. Copyright, 1920. 
Types | of | Mental Defectives | by | Martin W. Barr, M.D. | [two lines of 
titles] | and | E. F. Maloney, A.B. | Professor of English, Girard 
College | with 31 plates containing | 188 illustrations | Philadelphia | 
P. Blakiston’s Son & Co. | 1012 Walnut Street | Cloth, $3 net, pp. 
i-ix + 1-179 including index. Copyright, 1920. 
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