JUNE, 1950
351
devoted to the principles of eleotron microscopy and descriptions of commercially available electron microscopes, methods of sdjusting the electron microscope (particularly the RCA type E.M.U.), techniques of prepminx specimens, and discussion of mctd ~lm~lowiub:The m & d s given arc largely thwe tm~d il, t h ~ nuthrds . Inhorntory (La1,uralor.v of Phyiirkl Biology, Sationnl hstitutc of Hpnlth. Iktltcdt. 1lnrvlnnJ). m d thvo~-bthe ~~-~ descriptions are brief they may be expected to serve as a useful guide to the experimenter. The remaining five chapters are devoted to applications of electron microscopy to chemical and biological problems, in particular those of which the author has firsbhand knowledge. These chapters deal with study of surfaces, such as those of metal and of human teeth; viruses, including such aspects as the analysis of bacteria by bacteriophage and the meehmism of reproduction of viruses; macromolecules, such as sea-snail hemocyanin snd other protein moleoules, cellulose fibrils, collagen fibers, and antigen-antibody flocs; the structures of macromolecular solids, such as single crystals formed by viruses and mrtcromolecules. These diverse lines of research are illustrated in the hook by maoy beautiful electron micrographs, which taken altogether constitute one of the most attractive features of the book. An extensive bibliography, a t the end of each chapter, tends to remove the emphasis on the work of the author's laborrttory. ~
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that Concord, Catawha, and Delaware are Vilis labusea grapes not Vitia vinijera, as the heading appears to indicate. The bonds in some of the chemical formulas on p a e 429 and 430 are not placed properly. It would be helpful if in the next edition related topics were treated together with cross references used when necessary and if other minor changes were made. The book is easy to read for it is well set up. Proof was read carefully and there are many good illustrations and references. This book should prove useful to those who are beginners in food technology and to food technologists, chemists, and chemical engineers engaged in the processing of foods.
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OUTLINES OF FOOD TECHNOLOGY
Harry W. von Loesecke, Chemist, U.S. Department of Agricdture, Washington, D. C. Second edition. Reinhdd Publishing Corp., 330 W. 42nd St., New York, 1949. Seoand edition. vii 585 pp. 91 tables. IUusfrated. 16 X 2 4 cm. $7.50.
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ITIS the purpose of the second edition of this book to incorporate the advances in food technology which have been madesince the first edition was published about 8 v e m ago. In the present edition the major &tegories of f~od-~rodu%s, namely; dairy, meat, fish, grain, fats and oil, sugar and starch, and fruit and vage table products are discussed from the points of view of handling the raw materials, processing and preserving the foods, using food processing equipment and machinery, packaging and storing, and marketing. Thus the f i s t chapter is devoted to the manufacture of tin cans and glass jars and closures and the 14th to the storage and marketing of fruits and vegetables. In the main, the author has achieved his qhjective. The book could he improved by giving greater stress to certain food categories and by a better arrangement of the useful material it contains. For example, the author points out that dairy products constitute 45 per cent of the food consumed in this oountry, yet he devoted only 36 pages (48 if eggs are included) to this topic while approximately 185 pages are given to vegetables and fruits. An alphabetical arrangement is sdvantttgeous for encyclopedic coverage but in other instances it is more often a disadvantage. For instance, it is disconcerting to find oranges, grapefruit, lemons, and limes in that order together as a group under "Citrus fruits," whereas blackberries (Rubus uillosus) are discussed on page 52, loganberries (which are closely related to the blackberry a d raspberry) on page 88, and raspberries (Rubus strigosus) on page 113. Most of the essential oils are discussed in Chapter X I a n spices, relishes, essential oils, and extracts but the citrus essential oils rue treated in the citrus fruit section, Chspter 11. Grapes are considered on page 84 and raisins on page 111. There are many other instances of such separation or lack of separation of material. The illustration of the grapefruit knife on page 68 consisting of a blade riveted between 2 wooden grips is what a food-processing knife should not be. Sanitary knives are those having s. ouepieos hsndle made of metal or plastic and having several shallow grooves for a comfortable grip. It should he noted on page 85
MORRIS B . JACOBS
METALLURGY FOR ENGINEERS
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h C. Rolloaon, Delegate Director and Research Manager, Murex Welding Processes, Ltd., Waltham Cross, Hertfordshire, England. Edward Arnold d Co., London, 1949. Second edition. viii 339 pp. 63 tables. 179 figures. 14.0 X 21.5 om. $3.
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TEXTSan metallurgy written expressly for engineers perform an importrrnt function because mechanical, chemical, and other engineers make a larger number of simple decisions involving the use of metals than do metallurgists. Dr. Rolloson's "Metallurgy for Engineers," now available in a second edition, is an outstanding example of this type of book. The materid is presented clearly and enlivened by numerous references to practical applications. The illustrations, some of which are quite original, contribute greatly to the value of the book. The introductory chapters deal with mechanical testing and the macro- and microexamination of metals. A brief discussion of mechanical properties includes mechanical behavior a t high and low temperatures, fatigue, and brittle fracture. Visual inspection and metallographio analysis are stressed as basic metallurgical tmhninrwa~ . ~.... .
The swtion ~r solidification, equilibrium diagrams, nnd the deformation and unncaling of mctnli i.; a hi~1d.vcondcnsrd, simple trcatrntnr of marly of the ha& rlements of ~hvsicalnwtnllurrv. -. Such topics as shrinkage, gas porosity, segrigaiion, and internal stresaea are described adequately. Nucleation and growth, Xray diffraotion, ternary diagrams, and superlattices are presented very briefly. The short disouesiou of metal-working processes should be valuable to nouengineers. The specialized part of Dr. Rollason's book, whioh deals in a fairly detailed manner with carbon and alloy steels, cast iron, and nonferrous metals, comprises nearly two-thirds of the book. The last two chapters are devoted to metal joining and the measurement of high temperatures. The author of a text on metallurw for eneineers must decide how much space to ~lcroteI,, principles and Imw nruch to spccifir far[*. In this dilcmmn Dr. Rollson has fxvorrd factual infornut b n Cmrr fundnmrutxlr. Thr wisdom c>f dLeussing fcrrous b e fore nonferrous metals m y be questioned. The arrangement of material in this book is unfortunate in some other respects; powder metallurgy for example is included in the chapter on allay steels and the general subject of oomsion is discussed in the ohapter on stainless steels. A book written from the standpoint of British engineering practice m y appear to be of reduced usefulness in this country. I t is true that mention of puddled wrought iron or crucible steel could be omitted for American engineers. The British specification standnrds, some tmds names, s n d a fewtechnical terms used by the author are largely unknown in the United States. Dr. Rollason's book, however, is so comprehensivein its approach and so competently written that differences in terminology do not detract seriauslv from its value for use in this countrv. In fact. to of metallurw this concise ~ r i t i i hmesent,%: ~- American &dents .~. tion should be espccinlly stinr'&ting. Other6 intcreqtrd in metal lor^ maill not find a thorough trc'ltmrnt of fundnmcntalr in Dr. Iloll~wm'sbook lmt n good nrrount elen~entaryphysical
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