NA TURE 



2^9 



THURSDAY, XO\'£MBER 



5' 1914- 



DAIRY CHEMISTRY AXD DAIRY 

 CONTROL. 

 Dairy Cheynistry : A Practical Handbook for Dairy 

 Chemists and others having Control of Dairies. 

 By H. D. Richmond. Second edition, revised. 

 Pp. xi + 434. (London: Charles Griffin and 

 Co., Ltd., 1914.) Price 155. net. 



THE first edition of this book has been out of 

 print a good number of years now, and 

 many inquiries must have been made for the new 

 edition of "Richmond." This second edition will 

 therefore be welcomed by a large section of those 

 who are interested in dairying, for the information 

 it gives is difficult to obtain elsewhere. 



The main arrangement of the new edition is 

 similar to what it was before, and it would not 

 be easy to improve upon much of the subject- 

 matter. In the first chapter, for example, there 

 is a particularly clear account of the constituents 

 of milk, and sufficient detail of the chemistry of 

 the constituents is given to satisfy any inquirer. 

 Following upon this chapter comes one which 

 deals with the analysis of milk, and here are given 

 in detail the various methods of determining the 

 specific gravity and the formulae for calculating 

 the total solids, etc. The milk scale is also ex- 

 plained very fully. Attention may here be directed 

 to the author's water oven, which appears to be 

 admirably adapted to the drying of milk samples 

 if a vacuum drying apparatus is not available. 



The quantitative methods for the estimation of 

 boric acid and of milk sugar are given, and also 

 the gravimetric and volumetric methods for the 

 >timation of fat. Additional matter in this 

 chapter deals with the acidity of milk and the 

 method employed for indirectly estimating the 

 proteins by means of the aldehyde figure. 



The analysis of sour milk is dealt with very 

 fully and also the methods for the examination 

 of milk powders, which are now coming on to 

 the market in increasing quantities. The chapter 

 on the variation in the composition of milk calls 

 for no special remark, except that the paragraph 

 upon the influence of feeding, etc., upon the 

 composition of milk puts very clearly before the 

 reader what is known upon the subject. Those 

 paragraphs that deal with the composition of con- 

 densed milk and milk powders will be found very 

 useful for reference. There is also a great deal 

 : useful information contained in the chapter 

 pon the chemical control of the dairy, and by 

 means of it the chemist ought to have no difficulty 

 in checking the milk as it comes into the dairy 

 and ensuring that it leaves, whether as milk or 

 some other product, in a pure, clean form. 

 NO. 2349, VOL. 94] 



The determination of the fat percentage of milk 

 by centrifugal methods . (Gerber and Leffman 

 Beam) is gone into very fully, and much prac- 

 tical advice is given. 



A dairy chemist must also be something of a 

 bacteriologist, and there is a chapter devoted to 

 this side of his work. The outline of the chief 

 bacteria in connection with milk and the methods 

 of making nutrient media will be found useful. 

 In view of the fact that some authorities place 

 considerable reliance on the reductase and fer- 

 mentation tests, a little more detail of the manner 

 in which these tests are made would have been 

 helpful. Both these tests can be carried out 

 rapidly, and once the operator has accustomed 

 himself to them and taken due precautions, they 

 serve to give many valuable indications of the 

 cleanliness or contamination of the milk. 



The chapter on butter is excellent, all the chief 

 methods o( analysis being given in detail. For 

 comparative purposes a brief account of the manu- 

 facture of margarine would have been useful. 

 There has not been much alteration in the chapter 

 on cheese and other milk products, but \'an Slykes' 

 method for the estimation of products of ripening, 

 which looks as though it would become a standard, 

 is given. The last chapter deals with the calibra- 

 tion of apparatus, and if some of the juniors in 

 every laboratory were set to calibrate the burettes, 

 pipettes, etc., it would be an excellent training 

 and would show how inaccurate much of the 

 cheap glassware is. 



GEOLOGICAL BOOKS FROM AMERICA. 

 (i) Introductory Geology. A text-book for Col- 

 leges. By T. C. Chamberlin and R. D. 

 Salisburs-. Pp. xi + 708. (New York : Henry 

 Holt and Co., 19 14.) Price 2 dollars. 

 (2) Engineering Geology. By Prof. H. Ries and 

 Prof. T. L. Watson. Pp. xxvi + 672. (New 

 York : John Wiley and Sons, Inc. ; London : 

 Chapman and Hall, Ltd.. 1914.) Price 175. 

 net. 

 (i) 'TT^HIS is essentially an abridged edition of 

 X the "College Text-book of Geology," 

 published five years ago, and is perhaps the most 

 readable of the volumes contributed to geological 

 literature by these two distinguished American 

 teachers. In the process of concentration they 

 have avoided a jejune presentation of their sub- 

 ject, the treatment being interesting throughout. 

 A vivid sense of the out-of-doors aspect of geo- 

 logical study is given by a large number of fine 

 illustrations of the operation of geological 

 agencies in different parts of the world. 



The first 300 pages are devoted to geological 

 processes and materials. Here are described the 



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