plained ar being probably d m t o the secondary valences or unbalanced attraction* of the atoms on the face of the crystal lattice. A di~cusrion of surface energy and crystal growth follows the section oosurfaees and interfaces and the physieochemical phenomena are completed by a discussion of Brownian movement and kinetic mcrgy. The remainder of the book is devoted to a consideration of the ormerties of disoerse svrtems utilizing and emphasizing the importance of the principles discussed in the earlier part. Fortytwo pages are devoted to sols. 13 pages to gels, and the remainder of the book t o smokes, foams, and dimerse svstems containing more than two phase.. As an introductory text I can find nothing in the book worthy of rtifieism and much t o commend. I t is in my opinion the best book of its sire ~ h i e hhas yet appeared covering this field of chemistry. It could be used to advantage as a textbook in an introductory course in colloid chemistry where the students have a reading knowledge of Gennan. The German construction is not involved and the vocabulary does not contain many unusual (from the chemical standpoint) terms. There, however, is a rhythm and a literary style which makes it delightful reading. I also recommend it to those stvdents who are reading German in preparation for the language requirements for the higher degreee.
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ROSSAEBN GORTNHR The 4.Chemical Age" Chemical Dictionmy: Chemical Terms. D. Van No*traed Cornv*ny. Ewht V%rrin Street. Ncw York Cow. 1124
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This book is designed as the forervnner of a retics of chemical dictionaries t o be brought out by the publishers of The Chemical Age of London. I t ir a compilation of nearly 3000 general terms, used in organrc, physical, inorganic, analytical, and biological chemistry, particularly io the 6mt two subjects. But few names of specific substances are defined, there premmably being left for subsequent volumes. One of the most valuable features of the book is the extensive list of types of organic compounds and reactions. This list is more complete than that for any of the other branches of chemistry: yet it is not comprehensive enough "to meet the nee& of all those who have to consult not only original paperr or their abstracts but other lorms of literature as represented by reviews end modern textbooks" Definitions are usually clear and well illmtrated by equations, structural formulas or other examples. A s a rule care has been used in the selection of terms. There are, however, a number of ineonsirtencies bath in the choice of material and in the m e of symbols. I n the expression for the diffusion constant and in that for the ionic radius, for example, p has a different simificance.
Beryllates and zincatrs are listed alphabetically but not aluminates, sclenater, tellurates, or tungstater. Molal, the Bohr atom, KolheP reaction, centrifuge and ehromyl are among the other omission. in the alphabetical arrangement. Several errors have been made in definitions. Anion, for instance, is defined a. '-the positive ion furnished by an electrolyte;" cations as "the negative ions." T h e e terms are used correctly under the heading of ELectrolysis. Atomic number is incorrectly said to be lhr loto1 n u r n a ~of dacrronl in the =tom. - ~ ~ i ~ d ~ ~ - ~ ~ ~ f t reaction" should be Priedel-Crafts' reaction. Evidently a typogrnphical error was made in the mathematied statement of Graham's law. Many of these inran~intenciu aod errors might have been eliminated by proper editorial rupervidona suggestion for subsequent volumes. A11 things mnridered, the good points far ontweigh the faults. The baok .hauld prove t o be useful as a dictionary of general chemical terms.
M.C . S N B B ~ Introduction to Organis Research. By E. EIIMBPR B ~ .Ph.D. Profemor of Organic Chemirtry. Johns Hopkine University. 6 X St/,. Cloth, 35 PP. 84.50. Dr. Reid's baok is really broader than its title warrants one to expect. Only seven of its eighteen chapters are devoted to organic cbemistry. I t is rather a general survey of the field of chemical research with applications from the chemistry of the carbon compound.. To the teacher of high school chemistry, this book ought t o serve as an inviting introduction into the field of research. It ought t o give the student about to undertake post graduate in chemistry, same idea of what is before him. T o the director of investigative work, if gives a definite reference to collected material for fixing in the mind of the young experimentalit the ideals and methods of researeh together with s valuable collection of information as to the journal literature of chemistry and the imporrant secondary sources. It also makes a number of valuable suggestions for arranging permanent records of experimental work. The large number of quotations from authorities in modern scicntific research adds much general interest to the book. The subject matter is not presented in any striking or novel way, but is rather a painstaking accumulation of material not readily available. A large number of footnote references invite one t o fvrther study. Chapters dealing with organic chemistry are mare for the particular investigator in that field. and are full of valuable suggestions. But the work can be read with profit by any one who des i r e ~t o know more of the method for scientific investigation.
