BOOK •F•VlF. WS 55 the falsification of the predictions of a rival's theory we may only look for a result which will confirm our own theory. Only in one part would I presume to disagree with Prof. Davies - he believes that "adjusting the theory to fit the facts after some prediction is proved wrong is .... dangerous to the prestige of the theory". This is clearly true of much of the precise physical work to which Prof. Davies has contributed so much, but it may be less true in other areas, particularly those involving biological systems. In this case I would suggest that we must collect our facts, evolve a theory and then attempt to prove it wrong. If we are successful, I feel we are justified in revising the theory to fit the new facts. If we are not able to prove it wrong than we must try again and again. In this way, theories evolve and become nearer to the truth. This delightful book justified a very wide readership both scientific and other, for, as Prof. Davies says, "The boldness and imaginative sweep of many scientific hypo- theses, the necessity of checking them by experiment and the importance of criticism {even of established authority) are what should be taught to all." A. W. HOLMES. CRYSTAL DIAMONDS AND TRANSISTORS. L.W. 1Vlarrison, Pp. 312 q- Ill. (1966). Penguin Books, Harmondsworth, U.S.A. and Australia. 8/½. Here is an interesting technical book written for the layman. The theme of crystals covers a broad field of interest from ice and its relationship to weather conditions, through gemstones and geology to the modern world of solid state clectronics. Specialists who desire a general knowledge of technologies other than their own will find the book stimulating and written with good humour. The rheologist cannot expect to find any new technical material in the section discussing ice-cream, nor will the biologist find inspiration in the chapter on bones and teeth. But these topics, taken in perspective, could help the specialist to under- stand what his co]leagues are doing in other departments of his organisation. The names chalk, clay, silica, colloids, talc, alginates and liquid crystals are not so unfamiliar to cosmetic chemists, while the terms photography, lasers, transistors, fluorescent lighting and photocells indicate some of the modern technologies that owe their existence to the crystalline state. These subjects and many others are discussed for readers seeking information without unnecessary detail. J.D. CHESHIRE. SEMIMICRO QUALITATIVE ORGANIC ANALYSIS- THE SYSTEMATIC IDENTIFICATION OF ORGANIC COMPOUNDS. N. D. Cheronis, J. B. Entrikin, E. M. Hodnett. 3rd Edn. Pp. xi q- 1060 q- Ill. (1964). John Wiley, New York-London- Sydney. •Os. This is a new edition of a •vell-known and respected text that depends primarily on classical procedures: details are supplied for separation, purification and the determination of physical constants of functional groups of a most comprehensive series of compounds that are commercially available or of research interest. The basic organisation of the book is similar to that of the previous editions. Part 1

JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS comprises an exposition of the classical techniques of separation, i.e. crystallisation, distillation, sublimation and solvent extraction, but these are supplemented by the now common modern procedures of chromatography on paper, solid columns and thin layers and also by ion exchange, and gas/liquid and gas/solid adsorption. The second part deals with the preliminary examination and tentative classification of a compound, including differentiation by solubility, acidity and the 'class' tests. These two parts together account for nearly half of the book and constitute, some might consider, its chief paedagogic attraction even the practising analyst will still profit from their study. What is certain is that student and organic analyst alike will find use for the other two parts: the former gives procedures for the final characterisation of the unknown tentatively identified in Part 2. Methods are described and discussed for preparing the derivatives of carboxylic acids, alcohols and phenols, aldehydes ketones and acetals, carbohydrates, esters and ethers, halogen substituents, hydro- carbons and numerous nitrogen and sulphur functions. Spectroscopic methods (uv, Jr, nmr and mass) are mentioned briefly in 5 pages but are then supported by a very extensive bibliography: one is glad to see that a sound basis of practical analysis is taught before the tiro runs to the generally rapid but not always unambiguous ex- pedients of modern instrumentation. In an earlier chapter too, dealing with the determination of physical constants, as well as the interpolation of some theoretical discussion, there has been added some introduction to the use of instrumental methods. Finally, Part 4, comprising one third of the text, is a monumental compilation of 35 tables, containing characteristic constants and derivatives for about 7500 substances. Apart from their commercial or research significance, those compounds have been selected which have well defined atmospheric melting or boiling points and for which sufficient derivative or purely physical characterisation has been published. It is recognised that the race for up-dated lists for identification can never be won and in any event the organic analyst needs to identify his compound by its properties rather than conversely (hence the publication of such compendia as the 'Melting Point Tables of Organic Compounds' by Utermark & Schicke). There is also the problem of nomenclature: that adopted by Entrikin is somewhat arbitrary but on balance favours retrieval by the practising analyst. The text concludes with an appendix of relevant reagents, short accounts of the determination of acid, saponification and iodine values, and comprehensive subject and compound indices. Even the end papers are utilised: here are printed some succinct hints on action to be taken in common laboratory accidents and provision of first aid. Some years ago a reviewer remarked that the second edition was the "most comprehensive treatment of qualitative organic analysis currently available in a single volume" inspection shows that this edition contains physical constants for about 75øfo more compounds and their derivatives, which might be considered a very satisfactory growth rate in eight years! G. F. PHILLIPS