Exp~oslvss. John Read. Published by Penguin Books Limited, Harmondsworth, Middlesex, England, 41 East 28th Street New York, 1942. 160 pages. Illustrated. 11 X 17 cm., paper covers. This is one of the Pelican Books (published by Penguin Books Limited) which are on sale throughout England a t the moderate price, as we understand it, of six pence each. The price of the book is not marked upon it. Advisory Editors of the series are H. L. Beales, Reader in Economic History, University of London. and W. E. Williams, Secretary of the British Institute of Adult Education. Theauthor, Professor of Chemistryin the University of St. Andrews, is well known to readers of this JOURNAL.His name is a guarantee that the hook is authoritative in substance end wholly understandable, pleasing in style, easy and entertaining to read. I t is written in a popular manner, journalistically, t o convey a sympathetic understanding of the subject of explosives to a reader who has had no previous acquaintance with chemistry. We say sympathelic because it will make the reader realize that explosives serve many friendly purposes, that they are powerful civilizing i d n e n c e b g o o d for much else besides the killing of men. We say understanding because, without technicalities, it makes apparent the relationships of explosives t o the general economy of the times, t o fats, to cotton, t o coal, and t o the gases of the atmosphere. The author's dedication is "1242-1942 t o a future which shall see 'the marvellous power of art and of nature.' as foreshadowed by Roger Bacon, ranged wholly on the side of humanity." The author's sense of humor and the rightness of his insight are both illustrated by the following typical passage, chosen almost a t random. "Reverting now to the picture of carbon atoms as diminutive four-handed beings, it can be said that their social activities are unrivalled in the whole world of atoms. This
characteristic of carbon atoms is their unequalled capacity for fraternising among themselves. Atoms of other elements exhaust their powers of mutual hand-clasping by the time that three or four of them, a t the most, have joined in. Carbon atoms, on the contrary, enter into this form of association with the utmost zest, keepingat the same time their friendly contacts with other atoms, notably those of hydrogen, oxygen, and nitrogen." And another passage. "If animals were able to assimilate petroleum. life would perhaps he speeded up unpleasantly even for an age that makes a fetish of speed. Nature abounds in common sense. . . . "In her chemical mood, indeed. Dame Nature is a henign mother. Not content with endowing man with rich chemical storehouses of food and energy, she has savoured his dishes with salt ahd spices, delighted his eyes with hright colours and his nostrils with fragrant perfumes, and has clothed him in garments of fibrous cellulose and p r o t e i n ~ h e rcottons and wools and silks. She has ordained, with a care hardly less than grandmotherly, that no natural beverage shall contain more than about 15 per cent of alcohol; and even her poisons-her strychnine and morphine and atropine--have their beneficial uses. Finally, in her wisdom, she has refrained from including in her lavish chemical cornuco~iaanv substance of an exnlosive nature. . . . "I:xplosivrsarc purcly arrifiliul produrtams. . ' In his first surceisful attenllni ru makr an erplusivr, N\'nmre's wilful child mixed two rombu.til>lc materiala, charcoal and sulfur. with another substance, saltpetre, containing an abundance of oxygen in a condensed or combined form. . "Not content with the power of his first explosive--gunpowder-an has turned t o the concentrated organic energy of the carbohydrates, fats, coal, and petroleum, in fabricating the enormously powerful explosives of modem times. Into the molecules of substances derived from these sources, so stable and peaceful in their natural form, he has introduced a potential disintegrating influence in the form of nitro-groups (-Nod. These nitro-groups infect the molecules with instability, by virtue of the relatively lwse attachment of their constituent oxygen and nitrogen atoms. Nitro-groups are the fifth column-
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ists of the molecular world. When the proper moment arrives they bring about the complete collapse of the molecular society into which they have insinuated themselves." In a small and popular hook of this sort it is perhaps remarkable that so many of the most recent developments in the explosives art should be mentioned a t all. The author does not discuss nitroguanidine, hut does touch upon flash reducers, cooling agents, and moderants or deadeners for smokeless powder, on hexamethylenetriperoxidediamiue (HMTD), on trinitrotriazidobenzene, an tetracene, and on "Cyclonite, also known as Henogeu or T4." The book will help t o make many persons understand more clearly these essentially benevolent substances which have lately been elected to fulfil for a time the roles of assassin and murderer. TENNEY L. DAVIS NORWELL MISSACBVS~TS
EMULSIONSAND FOAMS. Sophia Bcrkman and Gustav Egloff, Universal Oil Products Comnanv. Chicam. Reinhold Publishing Corporation, New JorC,. 1941. k i i i 591 pp. 40 figs. 15 X 23 cm. $8.50. This very useful hook naturally contains an extensive section on petroleum emulsions since the authors are chemists in that field. They make the astounding statement that one-fourth of all the petroleum obtained in the United States carries emulsified water. Some pipe line companies refuse to transport oil containing over two per cent water, and a few set the permissible limit as low as one-half per cent. Many of these water-in-oil emulsions are difficult t o break, so there has developed much patent literature on the subject, ably discussed by Berkman and Egloff. The practical side of testing such emulsions is, quite properly, given adequate attention. Eight types of "demulsification" are listed: topping, heat treatment, chemical treatment, desalting, freezing, filtration breaking, electrical dehydration by alternating current, and centrifuging. Of these the chemical and electrical treatments and heat treatment under pressure are in most common use. The five chapters deal with: (1) The Theory of Emulsions and Foams, (2) Practical Knowledge of Emulsions (Emulsification). (3) Demulsification, (4) Asphalt and Bitumen Emulsions, (5) Laboratory Methods Used in the Examination of Emulsions. I t is interesting to note the extensive use of the asphalt type of emulsions for paints, roofing, pipe covering, and road surfacing. Froths and foams, surface tension effects, viscosity, volume relations, electrical charge, hydration of emulsifying agents, and orientation of films are well treated. This book will be verv helpful t o all workers in the emulsion field. H A W N. HOLMES
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O B B R L ~ NCOLLBOB Oa*nuN. OHGO
FLUORESCENT CAEMICALS AND THEIRAPPLICATIONS.Jack De Ment, Research Chemist, The Mineralogist Laboratories; Assmiate Editor, The Mineralogist Magazine. With a special chapter on Ultraviolet Radiation Sources by H. C. Dake, Editor, The Mineralogist Magazine. Chemical Publishing 240 pp. Company, Inc., Brooklyn, New York, 1942. xiii 11 figs. 13.7 X 21.7 cm. $425. I n a listing of nearly 3000 chemicals and their fluorescence, the author has included many new chemicals, some of which are comparatively rare. The chief concern of the book, aside from the extensive listing, is a presentation of the uses of fluorescent chemicals in the industries, arts, and sciences. A brief discussion of the fundamentals, and the basis for fluorescence analysis are included for the sake of clarity. The present volume follows a previous work, "Fluorescent Light and Its Applications," written with H. C. Dake. Of particular interest is a study of the actionof beta andgamma rays on water, with the production of abiotic ultra-violet light. Attention is directed by the author to the interpretations, possible from this study, of the lethal action radioactive substances exert on neoplasms, and the destruction these agents cause in normal tissues.
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