November 25, 1922] 



NA TURE 



695 



larval stage, mines the leaves of both celery and parsnip. 

 Owing to the concealed mode of life pursued during 

 this period of its development, the insect is exceedingly 

 difficult to kill by means of any feasible insecticide. 

 Mr. J. C. M. Gardner, who is responsible for the section 

 on. the celery-fly, suggests the use of a spray containing 

 chlororthocresol as a deterrent preventing the insect 

 from egg-laying on the plant. He also suggests that 

 a certain number of plants (presumably he means 

 those of the parsnip) should be left in the ground to 

 continue growth for a second year. Plants thus left 

 were found, in a private garden, to be heavily infested, 

 while neighbouring seedlings were only slightly at- 

 tacked. It is, therefore, possible that the two-year-old 

 plants might serve as a trap crop which, when heavily 

 infested, could be pulled up and burnt. The idea, 

 however, needs testing thoroughly on a practical scale. 

 Mr. K. M. Smith's account of the metamorphoses 

 of the carrot-fly is a useful contribution, and the only 

 complete description available. As regards control 

 measures, he suggests the application of 1 part of green 

 tar-oil to 99 parts of precipitated chalk, scattered 

 between the rows as a deterrent to egg-laying. Since 

 the eggs are deposited on the soil, and not on the plant, 

 it will be seen that a thin application of this mixture 

 may possibly also deter the young larvs from reaching 

 the plant, should it fail to act as a deterrent to egg- 

 laying. Other repellent substances have also been 

 tried by Mr. Smith, against both this insect and the 

 onion-fly, with varying results. The book is suggestive, 

 but it leaves the control of the pests with which it deals 

 still in the experimental stage. It is clearly printed, 

 and the illustrations are accurate. 



The Feeding of Dairy Cattle. By Prof. A. C. McCandlish. 

 Pp. xix + 281. (New York: J. Wiley and Sons, 

 Inc. ; London : Chapman and Hall, Ltd., 1922.) 

 125. 6d. net. 

 In no branch of the art of feeding live-stock does 

 practice tend to follow more closely the advance of 

 nutritional knowledge than in the feeding of the milch- 

 cow. The ease with which output can be measured, 

 and the consequent facility of assessment of food 

 requirements and economic returns, have rendered 

 feasible a systematisation of this branch of feeding 

 practice which is so far ahead of present possibilities 

 in dealing with other classes of live-stock as to justify 

 a specialised literature. The American student of 

 agriculture has been well catered for in this respect in 

 recent years, and the volume under review represents 

 the latest addition to a list already long enough to 

 warrant a critical attitude towards further additions. 

 The justification of its issue does not rest on any ap- 

 preciable novelty of material or method of presentation, 

 but on the skilful manner in which the author has 

 succeeded in giving in so few pages a thoroughly 

 practical, lucid, and trustworthy survey of the subject, 

 which cannot fail to be most useful to the practical 

 man and practically minded agricultural student, for 

 whom it is intended. The book is divided into five 

 sections, the earlier sections being essentially scientific 

 and leading up to the more detailed exposition of 

 feeding practice, to which the last, and largest, section 

 is devoted. The most recent developments in the 

 science of nutrition receive adequate notice, and their 



NO. 2769, VOL. I 10] 



possible bearing upon practice is treated with com- 

 mendable judgment and restraint. The book worthily 

 fulfils the purpose for which it was intended, and may 

 be cordially commended to progressive dairy-farmers 

 and students in " farm institutes." 



Lehrbuch der anorganischen Chemie. Von Prof. Dr. 

 Karl A. Hofmann. Vierte Auflage. Pp. xx + 751 

 + 7 Tafeln. (Braunschweig : F. Vieweg und Sohn, 

 1922.) 300 marks ; 245-. 

 The fact that successive editions of Dr. Hofmann's 

 " Inorganic Chemistry " have been issued in 1917, 

 1919, 1920, and 1921, is sufficient evidence of the 

 popularity which it has achieved in German-speaking 

 countries. The scope is very similar to that of English 

 text-books of similar price, although it differs from 

 these in containing a large amount of matter in small 

 type and very few illustrations. Characteristic features 

 are the postponement to the end of the book of a 

 series of special subjects, which include explosives, 

 co-ordination-compounds, the structure of crystals, 

 radio-active substances, the structure of the atom, 

 and the distribution of the elements. The theoretical 

 introduction is therefore extremely brief, and the 

 periodic classification of the elements is discussed in 

 the body of the book without any reference to atomic 

 numbers or isotopes. In view of the scantiness of the 

 illustrations it is remarkable to find six figures given 

 up to pictures of burettes, pipettes, and measuring 

 flasks and cylinders in a section dealing with caustic 

 potash. The seven plates which illustrate the flame- 

 spectra of the elements, the line-spectra of the principal 

 gases, and the absorption spectra of the rare earths 

 are, however, excellently reproduced, and form a very 

 pleasing appendix. It is, however, doubtful whether 

 English readers will care to face the handicap of a 

 foreign language in order to obtain instruction which 

 they can assimilate with much greater ease from text- 

 books in their own language. 



Radio for Everybody. By A. C. Lescarboura. Edited 

 by R. L. Smith-Rose. Pp. xii + 308. (London: 

 Methuen and Co., Ltd., 1922.) 75. 6d. net. 

 Most people are interested at present in radio-broad- 

 casting, and there are many who are contemplating the 

 purchase of a receiving-set. It will be of interest to 

 them, therefore, to know how broadcasting has fared 

 in America and the kind of programmes which are 

 daily issued to the public. Specimen copies of these 

 programmes are given. It appears that vocal and 

 instrumental music, speeches and " talks," sermons 

 and stories for children are the most popular items. 

 The book contains an interesting chapter on the 

 development and present position of radio-telephony 

 in Great Britain. It is anticipated that radio-broad- 

 casting will soon be as popular in this country as it is 

 in America. We think, however, that the user of a 

 receiving-set will find that on about one of every five 

 days in this country receiving will be seriously interfered 

 with by atmospherics. The rest of the book gives a 

 popular but accurate account of the various kinds of 

 radio-apparatus. There is no doubt that the mystery 

 and fascination of the art of radio-communication is 

 attracting many boys to take up applied electricity 

 1 as a career. 



