172 



NA TURE 



[June 22, 1905 



growing in gardens and near the towns, and he does 

 not describe many scrambles up into the distant 

 mountains. But of the wild flowers to be found on 

 the hillsides or up the torrent beds no better guide 

 could be afforded than the beautiful series of coloured 

 illustrations distributed throughout the text. It is 

 possibly a pity that the figures are mostly printed 

 with black outlines, and it might be thought 

 preferable to have them printed on plates instead 

 of mixed up with the letterpress. In addition 

 to flowering plants, a number of the characteristic sea- 

 weeds have also been illustrated, and several charming 

 little sketches of Riviera coast scenery, in the form of 

 headings to the descriptions of the five different holi- 

 days spent by Prof. Strasburger on the Riviera, are a 

 welcome addition. K\\ these illustrations have been 

 tastefully drawn and coloured by Fraiilein Reusch. 



G. H Bry.^n. 



INTERNATIONAL PHYSICS. 

 Reciieil d'Experiences elementaires de Physique. By 



Henri Abraham. Part ii. Pp. .xii + 454. (Paris: 



Gauthier-Villars, 1904.) Price 6.25 francs. 

 \X7'E have already reviewed the first part of this col- 

 lection of physical experiments, which has been 

 gathered together under the auspices of the French 

 Physical Society. A large number of physicists from 

 all over the world have participated in the collaboration 

 by sending both descriptions of experiments and biblio- 

 graphical references, and the editor's work has con- 

 sisted in giving as much homogeneity as 'possible to 

 the products of this multiple collaboration. 



The present and concluding part embraces the sub- 

 jects of acoustics, optics, electricity and magnetism. 

 On the whole, the experiments in this part are of a 

 more difficult and elaborate kind than those previously 

 described. This is to some extent, no doubt, due to 

 the nature of the subjects treated. General manipula- 

 tion and mechanics required less reference to be made 

 to complicated and e.xpensive apparatus than the sub- 

 jects considered here. As a consequence of this the 

 private student who has no access to a properly 

 equipped laboratory will find much greater difficulties 

 in his way. He will still find a field for work in acous- 

 tics and light. With a few springs and wires a con- 

 siderable amount may be done in sound; and, in the e.x- 

 periments on light, homely articles like pins and cham- 

 pagne bottles are freely made use of. But in elec^ 

 tricity and magnetism he must be prepared for greater 

 outlay in apparatus. We lay stress on this point, be- 

 cause in our previous reference we recommended the 

 book strongly to the private student with a taste for 

 practical mechanics. 



The present part will be found of greatest utility to 

 the schoolmaster eager for hints in the arrangement 

 of class and lecture experiments. One special feature 

 in the descriptions is that in most cases the dimensions 

 of the apparatus which have been found to work well 

 are given. This will certainly save a teacher a great 

 deal of time, which otherwise he would need to spend 

 in experimenting himself in order to discover the suit- 

 able size and shape of his apparatus. We do not hesi- 

 tate to say, however, that time so spent is never lost, 

 and if in the busy workaday world of the teacher some 

 NO. i860, VOL. 72] 



means for saving of time is essential, it has its disad- 

 vantages. 



It is usually only by the somewhat laborious method 

 of trial and error that one learns the conditions neces- 

 sary for success. 



There does not seem to be much in the volume which 

 is absolutely novel as regards style of experiment. The 

 aim, obviously, has been to describe as simple experi- 

 ments as possible illustrative of all the common laws 

 of physics. This description is in all cases very brief. 

 There is no introduction of theoretical considerations ; 

 nor is there any attempt to make the subject attractive 

 to a general reader. A figure, a short account of the 

 construction and mode of using the apparatus — that is 

 all. 



In some cases the suggestions are open to criticism in 

 minor details. Thus, vibrating springs, which ought 

 to be attached to a fairly solid support, are shown 

 screwed to a slender skeleton wooden box. But in the 

 /nain the suggestions seem excellent, and there are few 

 teachers who will be able to learn nothing from them. 



The diagrams are not always clear ; nor are they such 

 as to give the book an attractive appearance. 



Briefly, the collection is meant for the teacher and 

 not for the student. To the former it is commended, 

 with the hope that he will be able to give life to these 

 somewhat dry bones by instilling his own individuality 

 into them. 



LIGHT AND HEALTH. 

 The Effects of Tropical Light on White Men. By 

 Major Charles E. Woodruff. Pp. vii + 358. (London 

 and New York : Rebman, Ltd., 1905.) Price los. 6d. 

 net. 



THE title of this book gives little idea of the enor- 

 mous field traversed by the author, or of the 

 amazing conclusions at which he has arrived. We 

 understand that the work is intended for laymen as 

 well as for medical readers, and particularly for 

 Americans about to reside in the Philippines. No ex- 

 ception can be taken to the advice given by Dr. Wood- 

 ruff in his concluding chapters. The necessity for 

 opaque white clothing, and of sufficient protection to 

 the head; the paramount importance of the siesta, and 

 of avoidance of work and social functions in the middle 

 of the day are recognised by Europeans living in the 

 tropics. The suggestions as to the selection of suit- 

 able recruits for the army in the Philippines are admir- 

 able. 



But it is impossible to accept many of Dr. Woodruff's 

 deductions from the scientific observations which he 

 so largely quotes. Even if we take it for granted that 

 the " death-rate of a place is proportional to its sun- 

 shine and inversely proportional to its latitude, other 

 factors being eliminated," does it follow that the death- 

 rate is dependent upon the amount of light, and have 

 the other climatic conditions, and especially the 

 parasitic insect life, no influence? Dr. Woodruff 

 would have us believe so. He informs us that 

 light is like alcohol, tea, coffee, and other stimulants. 

 In moderation, it is beneficial; in excess, it is harmful. 

 " We can do without it, but our metabolism is too 

 sluggish or defective if we do not get it." Excess of 



