42 



NATURE 



[October 7, 19 15 



or gromel, and flag, gladen, or water-segg for 

 the wild iris. 



There is throughout the book a sense of pun- 

 gent fragrance as of a bunch of herbs, and the 

 "chaplet" is, as the quoted foreword claims, 

 indeed "not short in savour." 



R. & L. H. 



OUR BOOKSHELF. 



The Analysis of Non-Ferrous Alloys. By F. 



Ibbotson and L. Aitchison. Pp. vii + 230. 



(London: Longmans, Green and Co., 1915.) 



Price 75. 6d. net. 

 At such a time as this, when there is a large 

 demand for metals and metallic alloys of all de- 

 scriptions, it is of the greatest importance that 

 the manufacturers and users of these materials 

 should have at their disposal rapid and accurate 

 means of controlling the chemical composition of 

 the goods they handle. 



Until comparatively recently the "commercial" 

 chemical analysis of non-ferrous alloys has received 

 but little attention, at any rate from those most 

 concerned, so that one has been forced to go for 

 one's information to a series of widely scattered 

 original papers in the various scientific and tech- 

 nical journals. A text-book embodying all the 

 best of the information at present available is 

 therefore exceedingly welcome. 



The work under review may be divided broadly 

 into three parts. The first part enters into a de- 

 tailed description of the most recently devised 

 apparatus for electrolytic analysis, and discusses 

 the main theoretical considerations underlying the 

 successful deposition of the metals. 



The second part reviews the action of sulphur- 

 etted hydrogen on solutions of the metals under 

 varied conditions of acidity, temperature, concen- 

 tration, and time. Then follows an exhaustive 

 description of the best methods for the estimation 

 of the various metals in solutions of their salts. 



The remainder of the book is devoted to the 

 application of the foregoing methods to the analy- 

 sis of brasses, bronzes, "white metals," and other 

 alloys of industrial importance. 



The value of the book is enhanced by a very 

 complete bibliography. The book should prove 

 of great value to works chemists and to the more 

 advanced students in technical schools. 



B. W. Drinkwater. 



Science of Dairying: a Text-hook for the use of 

 Secondary and Technical Schools. By W. A. G. 

 Penlington. Pp. viii + 260. (London: Macmil- 

 lan and Co., Ltd., 1915.) Price 25. 6d. 



This volume covers a very wide range, and is 

 intended to be used as a text-book of dairying in 

 secondary and technical schools. It deals first 

 with the composition and properties of milk, and 

 gives particulars of the methods employed in the 

 detection of adulteration. Two chapters are de- 

 voted to bacteria and the important part they play 

 NO. 2397, VOL. 96] 



in dairying. A later chapter gives working 

 details of the two best known rapid methods for 

 the estimation of fat in milk. The first of these — 

 the Babcock test — is not employed commercially 

 in Great Britain, but is common in Australia, New 

 Zealand, and Canada, whereas the second test — 

 the Gerber — is universally practised in this 

 country. 



The principles, and outlines of the practice, of 

 butter- and cheese-making are given in a clear 

 and concise manner. The author then passes on 

 to consider the physiology, feeding, care, etc., of 

 ithe cow, and some of the common diseases to 

 which she is subject. A chapter deals with arith- 

 metical problems arising in dairy practice. 



The book is written apparently for those who 

 take up dairying more as a subject of examination 

 than as an end in itself, and it is a little difficult 

 to see to what class of English readers it will 

 especially appeal. Without question, the educa- 

 tional value of such a work is considerable, but as 

 dairying- as a subject is not generally taught in 

 the secondary schools in this country, the demand 

 would appear to be limited to those attending a 

 county dairy school, particularly those who are 

 not following a systematic course of training. In 

 the latter case the details are Insufficient, but as 

 introductory to the subject all students — ^whether 

 short or long course — would benefit by a study of 

 the book. 



The Internal Combustion Engine: a Text-hook 

 for the Use of Students and Engineers. By 

 H. E, Wimperls./ New and revised edition. 

 Pp. xvi + 319. (London: Constable and Co., 

 Ltd., 191 5.) 65. 6d. net. 

 Since the first edition of this book was published 

 in 1908, there have been many important develop- 

 ments, both scientific and practical, In the internal 

 combustion engine. These developments have 

 necessitated many changes and additions in the 

 present volume. The book is divided into three 

 sections, the first of which treats of the theory 

 of the subject. After describing the more ele- 

 mentary theorems in thermodynamics and the 

 cycles employed, the author gives a very good 

 account of the numerous experiments which have 

 been made on explosions In closed vessels, and on 

 temperatures inside the working cylinder. The 

 second section deals with gas engines and gas 

 producers, and includes information regarding 

 the Humphrey gas pump, gas turbines, and 

 Hopkinson's water-injection system. Methods of 

 testing and of reducing test results are also given. 

 The third section deals with oil and petrol engines 

 and contains a good discussion on the Diesel 

 engine, and on petrol engines for motor-cars and 

 aircraft. 



The illustrations are very good and clear. At 

 the end of each chapter is .given a number of 

 excellent exercises, many of which have been 

 taken from recent Cambridge examination papers. 

 The book Is very well adapted for the use of 

 students, and has the merits of being moderate 

 both in size and price. 



