BOOK REVIEWS 53 fatty acids and methods for the detection and determination of a number of anti- oxidants. Under "Iodine Value", only the popular and well-tried Wijs method and the Hofmann and Green modification are described. Sully's stearic anhydride process for determination of hydroxyl value is referred to, but not described in detail and the reader is referred elsewhere for a description of the fietermination of thiocyanogen value. This seems a pity in a practical handbook and it might •vell have been preferable to include some newer and less known methods such as that of Sully rather than those which, like the acid value and iodine value, can be readily found elsewhere. The headings under each determination in this section of the book, e.g. Explanatory Note, Principle etc., do not always fulfil the promise inherent in the title: this applies especially to the heading 'Principle'. Micro and semi-micro methods are becoming increasingly popular and, of course, many of the newer physical methods described are truly micro-methods. The semi- micro Kjeldahl process is now an accepted method, but semi-micro modifications of other classical inethods such as, for example, the l{eichert process and There's microscope slide method for iodine value receive no mention. The section on Fat Products contains, among other useful information, methods for the detection of colouring matter and a spectrophotometric method for the determination of benzoic and sorbic acids in fatty products. The section on specialist techniques deals with many of the newer physical Inethods and also contains chapters on such varied subjects as the assessment of variability in routine analysis, the direct determination of trace metals without ashing and accelerated stability tests. It is a pity that the book is marred in places by loose or obscure English and the use of inelegant expressions such as 'weigh off' and 'distil off'. An example of obscure English is the definition of unsaponifiable matter in p. 123 - "By the content of unsaponifiable matter is understood the percentage, calculated on the original fat (Note 1), of natural, unsaponifiable matter present in the fat (sterols and hydrocarbons), and organic unsaponifiable matter not volatile a.t 100øC (mineral oils) which are generally absent from fats". This book contains much material that is useful and not readily accessible else- xvhere and the section on specialist methods and techniques is particularly interesting. Most analysts will have something to learn from this section alone. References to the original literature appear to be adequate and are given as notes at the foot of each page. S.J. BUSH. SUBMICRO METHODS OF ORGANIC ANALYSIS. R. Belcher. Pp. viii d- 173 d- Ill. (1966). Elsevier Publishing Co., ,4rosterdam-London-New York. 55s. Professor Belcher is an entertaining and stimulating lecturer his writing bears the same imprint. This book describes the techniques for submicro analysis of organic compounds that he and his colleagues at Birmingham University have deve- loped since 1951. Much of the individual procedures have been published in the JCS but he was unwilling to collate them in a single monograph until he had solved the most difficult but key method- the scaling down of the determination of hydrogen. The highly successful and widely used Pregl ultimate analysis had constituted a reduction by a factor of 100 from the classical half a gram or so to about 3-5 rag

JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Professor Belcher has made a similar advance. His analyses require only 30-50 micrograms of pure material (i.e. about the smallest amount conveniently handled and seen) but his quantity can be reduced to 15 micrograms or- for certain analyses- raised to 100 micrograms. He gives methods for all the elements commonly encoun- tered in organic substances and several functional groups the precision obtainable- usually better than «•o absolute- compares very favourably with conventional micro-analysis. The submicro methods are essential where only very small amounts of sample can be spared - as in natural product chemistry or the results of multi-stage syntheses. For each technique the background is discussed in sufficient detail for its understanding, and then the procedure and any special apparatus (kept to a minimum) described thoroughly and unambiguously. At this level gravimetric finishes are scarcely practicable, although Belcher, with the Oertling Co., are responsible for the commercial development of a quartz fibre torsion micro-balance for weighing samples to + 2 nanograms. Instead he relies mainly on volumetric procedures using the well-tried Agla syringe as the basis of his micro-burette. However for certain elements (e.g. fluorine, phosphorus and arsenic) he has had recourse to spectrophotometric finishes and for carbon and hydrogen determination he has used a manometric method. There is a fascinating account of early difficulties with the sub-micro determination of water from combustion of hydrogen: a wide variety of methods for the quantitative conversion of water into a readily measurable gas all failed to be reproducible or exhibited increasing blank values. Ultimately he opted to employ direct manometrcic measurement of water vapour taking exceptional precautions to avoid adsorption on glass surfaces. Other chapters, in addition to nitrogen, halogens and sulphur, include the determination of carboxyl, alkoxyl, N-methyl acetyl, carbonyl (aidehyde and ketone), olefinic double bonds, thiol, nitro and nitroso functional groups there is also a section describing a corresponding scaling down of the conventional cryoscopic determination of molecular weight. All chapters have a list of citations and there is a short but adequate index. This monograph will prove of invaluable assistance to any organic chemist engaged in the analysis of compounds of which only sub-milligram amounts may become available. G.F. PHILLIPS. THE SCIENTIFIC APPROACH. J.T. Davies. Pp. x q- 100 q- Ill. (1965). Academic Press, London/New York. 32/6. In many walks of life we are dealing with the more or less unknown and are having to predict. This is equally true whether we are deciding the best form of advertising for a product or how to invest some money, or the next experiment in fundamental research. In all cases we are (or should be) consciously or unconsciously following "The Scientific Approach". This eminently readable book by J. T. Davies clearly and unambiguously points to the correct way of operating, drawing on examples as diverse as intramolecular forces and bridge building. But the last chapter of the book extends the treatment beyond the bounds of physical science into economic theory and human affairs. The book develops logically and elegantly, dealing with the origin, testing and confirmation of theory, before demonstrating the application in engineering and in simple science and the art of prediction. There are many lessons for us all our atten- tion is drawn to the fact that while we may design our experiments to demonstrate