VOL
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orientation 01 moleculls on surfaces and a t interfaces, adrorpliun, t h e drcl"m1 proprrfica of colloidal wstemr i n c h d m e u c r mcsaurcmeot3 of the magnitude of the electrical charges on surfaces, the optical properties of colloid systems. peptiration, precipitation and coagulation, the characteristics of emulsoid sols with especial mention of the protein., and clopen with s d i c c u s r i a of the Donnan equilihrivm and membrane potential.. I n spite of the fact that all of there items (and more) are diseused in the few napes . . of the "01. "me, there are included in the text the essential mathematical formulas which it wodd he neeersary to use in order to calculate the various phyrico-chemical eonstants from experimental data. Not only that. but as a genera1 rule there is a complete derivation of these formular. stated so simply that anyone with a minimum of scientific training could easily follor the theories which underlie the formulas. There is much t o commend and little to eritieire. Perhaps the most surprising omirsion oecurs in the portion devoted to the question of electrolytic diswiation, where the theories of Arrheniur and of Ootwald are stressed but no mention is made of the newer theories of Debye. On page 181 the author erplainn the widely different behavior of proteins and agar as being due to the fact that protein. are capable of forming salts with acids and barer, whereas agar is a "neutral emulroid" and consequently is not complicated by changing electrical f0m.n. In as much as agar has been definitely shown t o be the calcium salt of a substituted sulfuric acid of the lormula R - O S O A H , where R is a complex polyraerharide, the idea that i t is a "neutral emul$oid" will not hold, and some other explsnation must be found to explain its reactions as eontraated with those of the proteins. The ereential laws of physical chemistry and of colloid chemistry are presented in this volume. Nevertheless the reviewer doubts whether there in any group in America which will profit by it. I t is far too brief f a r use in an extended course in physical chemistry and the same statement applies to its use as a referenee work, for which. of course, i t n a s never intended a3 is evidenced by the fact that there are very few literature citations. I t would be of great value to our medical students, but the fact that it is in a foreign language ail1 be an impassible barrier to its use ao a t e r t in our medieel ~ c h m l s . Ross A x s n Gomrnra
Chemishg to the Time of Dalton. E. J. How**no, M.A.. M.Se.. F.I.C. (Science Master a t Clifton College. Bristol, London). Oxford University Press, London. 1925. 128 pp. 12 X 18.5 em. 30 illurtrations. $1.00 net. The book is a short sketch of the history of chemistry t o the time of and including the work of Dalton. I t is written in a readable style and for B volume of this size is one of the most s t i r -
of the high lights in the developfactory a-ts ment of chemistry that can be put in the hands of the genera1 student. Chapter I , which is headed "Chemistry in Greece. Empt. and Islam;. is largely devoted to the Arabian contribution.. The author is an expert in this field and has put in a concise form some very interesting data. Some of Jabir's (8th century) rrulea for the practice of chemistry might well he ported io the freshman laboratory of today. For instance: (a) The operator should know the reason for performing each operation. (b) The instructions should he properly understood. (c) The impossible and profitless should be avoided. (d) He must have leisure t o perform his experiments, together with patience, reticence, and perseverance. Hearsay and mere assertion, according to Jabir, have no authority in chemistry. Chapters I1 and 111, "Chemistry in Europe the piftcenth century" afford a of that involved period which is covered a t length in Stillman's "The Story of E a r b Chemistry." The remainder of the text is largely devoted to the work of Mayow. Boyle.1 Black, Cavendish, Seheele, Priestley, Lavoisier. and Dalton. These are, with two exceptions, English chemists. and the casual student might get, in consequence, a not altogether aecvrate perspective of the relative values of contributions outride of England. More space might well have been devoted to the great Slsedish chemist, S c h e e l c a n d to others on the continent. However, i F i s a very sueeessful volume and should inspire further reading in the history of chemistry. The author, it might be said, takes en active interest in the development of School Seience and in Chemical Education in England.
P. B. DAINS Phgsikochemisches Praktilrum. Dn. A. T r r r e ~ . Sammbung nafvrwissennehaftlieher Praktika. Band 11. Verhg agvo Gehruder Borntraper, xv pp. 16.80 Gold Marks. Berlin. 380
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There are several featurrs of interest to be gathered from this praetical physical chemistry text. From the preface, i t is evident that new regulations for the Vnbonds examinations in Germany now call for examination in practical physical chemistry in addition t o the traditional practical tert. for all would-be doklorondcn. The author is 01 the opinion that the preparatirm for such a test can he ssured in r h weeks of whole-day practical exercise. He also portulateil that the exercises shall not be of the ready-pre-
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1 On page 69 there is a reprodvction of the title psge of the h t edition of B0,le.s ..The Seeptied Chymist." Profeuor Tenncy L. Davis of M. I. T. has an interesting article on this same title page in Isis, 8 , No. 26, 71-6 (1825).
