424 



NATURE 



[December i6, 19 15 



calculus course for engineers. The preliminary 

 work appears to have been selected solely with this 

 end in view. 



It is rather a formidable-looking volume, con- 

 taining nearly 500 pages ; and it would be more 

 readable : if there was some variation in the type 

 (in itself very good) employed. There are many 

 signs of individuality in the methods of treatment 

 and in the choice of subject-matter; the examples 

 are particularly stimulating, and on this account 

 alone teachers would do well to examine it. The 

 sections on periodic functions and harmonic 

 analysis deserve a special word of praise. 



(5) This small text-book contains in a compact 

 form the elements of practical drawing. The 

 author writes from the point of view of one who 

 has realised from industrial work, the .importance 

 of accuracy in the workshops, .and . he , insists 

 throughout on the need of close attention to con- 

 ventional notation and lucidity of expression. His 

 diagrams are clear, and his explanations . are 

 couched in simple language. 



For most students descriptive geometry is not 

 an easy subject ; it requires a power of visualising, 

 which comes only after long perseverance and 

 practice. Such a book as this seems to us to 

 give as much assistance to the student as he can 

 receive from outside ; a grasp of the subject can 

 only be obtained by his own diligence. 



OVR BOOKSHELF. 

 La Radiologie de Guerre. Manuel Pratique du 



Manipulateur Radiologiste. By G. Massiot 



and Biquard. Pp. viii + 224. (Paris: A. 



Maloine et Fils, 1915.) Price 3.50 francs. 

 A NEW impulse has been given by the war to 

 those who desire to say over again what has been 

 often and well set out already in text-books deal- 

 ing with the practical applications of X-rays. 

 Nevertheless, it must be ^admitted that extra- 

 ordinary inventive effort has been called for of 

 late regarding the design of new apparatus to 

 meet special and unusual conditions ; and, in . so 

 far as a new book on the subject deals con- 

 scientiously with this fresh phase, it should prove 

 useful in practice. 



The work under review suffers somewhat from 

 the defect that the authors are concerned with 

 the appliances designed and made by one firm 

 only. But if in one respect the book has the 

 limitations of an elaborated trade catalogue, it 

 also has the great merit of clearness and sim- 

 plicity. It contains a large amount of general 

 information relating to X-ray technique which 

 should not only be invaluable to the beginner, 

 but serve also as a guide to all who have to 

 organise X-ray departments for war. purposes. 

 For instance, the device for the wet racking of 

 plates described on page 136, at first sight a small 

 NO. 2407, VOL. 96] 



matter, assumes importance v.-hen many negatives 

 have to be developed and examined rapidly. The 

 effectiveness of the method recommended has, in 

 fact, been proved at one of the military hospitals 

 in this country, where it has been adopted since 

 the outbreak of war and where sometimes 200- 

 plates have to be dealt with in a day. 



The book is full of useful detail of this sort,, 

 and more than one hundred pages are devoted 

 to the question of the localisation of imbedded 

 foreign bodies. The whole elementary ground of 

 practical radiography is fairly covered, although 

 no mention is made of stomach examinations and 

 the technique of what may be called the " higher 

 X-ray diagnosis." There are illustrations of 

 folding couches, portable X-ray outfits, and so 

 on, as well as ambulances that are complete 

 radiographic departments on wheels. 



Within the limits stated in the early part of 

 this notice the book may be thoroughly recom- 

 mended. C. E. S. P. 



Laboratory Manual of Horticulture. By Prof. 



G. W. Hood. Pp. vi + 234. (Boston and 



London: Ginn and Co., 1915.) Price 45. 6d. 

 A COURSE in horticulture is by no means easy to 

 devise, but it is certain that so far as the craft 

 of the horticulturist is concerned the best place 

 to learn it is in the garden, the potting-shed, and 

 the frame-yard : these must constitute the labora- 

 tory. Hand-in-hand with training there should 

 go work in botany, especially in vegetable physi- 

 ology, in elementary chemistry, and physics, 

 with the double object of inculcating scientific 

 method (which should not be ignored in the 

 garden) and of education in a knowledge of how- 

 plants grow. 



Judged by this standard this "Laboratory 

 Manual of Horticulture " falls lamentably short. 

 It consists largely of observations on buds, 

 corms, and fruits, and of experimental exercises 

 with seeds, all of which fall into the realm of 

 horticultural botany, and of exercises on making 

 cuttings, grafts, buds, grafting-wax, fungicides 

 and insecticides. It is intended as a general 

 course in horticulture, but is really a series of 

 exercises which have a more or less direct bear- 

 ing upon practical plant-growing. It is true that 

 it is recommended that after fundamental prin- 

 ciples are mastered practice should be given in 

 pruning and spraying, but even if this is done, 

 a course which does not include tillage operations, 

 potting, seed-sowing, planting, propagation 

 (apart from the mere making of cuttings, etc.), 

 watering, heating, ventilation, pollination, etc., 

 cannot properly be called a course in horticulture. 



After all, it is mainly with the title that we 

 quarrel. The book cannot fail to prove sugges- 

 tive to the teacher, or the working of the exer- 

 cises profitable to the taught. The exercises are 

 interleaved with blank pages for the student's 

 notes and report, but we do not quite like the 

 temptation to "copy" which the illustrations 

 afford when directions are given to draw some- 

 thing. F. J. C. 



