August 14, 1913] 



NATURE 



605 



brief notes on variations of climate, and on climate 

 culture, he concludes with an account of the 

 climate of each of the five continents. The book 

 is well written and arranged, and the author has 

 made discriminating- use of recent investigations. 



(2) It is a commonplace that men seize upon 

 the exceptional and regard it with especial interest 

 while they let pass unobserved the beautiful and 

 wonderful processes which are taking place every 

 day. Herr Sassenfeld has written his book with 

 the object of stimulating and guiding the youth of 

 Germany in the observation of the recurring pheno- 

 mena of meteorology, which may be for all, as 

 they are already for some, a source of interest 

 and pure delight. 



In fewer than 200 pages the author covers the 

 whole ground of meteorological observation and 

 investigation : he devotes a chapter to the tem- 

 perature of the upper atmosphere, giving 

 Wagner's results for the temperature at heights 

 of 1, 2, . . 10 km. for January and July, and for 

 the whole year. In a small table he indicates the 

 characteristic lag in annual variation of tempera- 

 ture by showing how the difference between the 

 autumn and spring temperatures increases with 

 altitude. Special attention is given to clouds, and 

 three excellent illustrations of different types are 

 reproduced from photographs lent by Dr. Suring, 

 of Potsdam. Pressure is introduced in the middle 

 of the book, after temperature, water vapour, dew, 

 hoar frost, clouds, and rainfall have been con- 

 sidered. Although pressure is of fundamental im- 

 portance in the study of meteorological processes, 

 it introduces an idea which is strange to the mind 

 and difficult of apprehension ; and it is probably 

 wise to impart some knowledge of the meteoro- 

 logical phenomena which affect human life most 

 directly before seeking to teach the bases of 

 dynamical meteorology. Wind, types of weather, 

 and electrical and optical phenomena are next 

 discussed in turn, and an appendix contains a 

 valuable set of monthly rainfall normals for about 

 forty places. The book is printed in Gothic type. 



(3) This is a discursive book which shows that 

 the author has read very widely : he deals with 

 the atmospheric circulation in winter and summer 

 in the northern and summer hemispheres, and 

 shows that he is acquainted with most of the litera- 

 ture on the subject. In the second and third 

 sections he deals with atmospheric electricity and 

 terrestrial magnetism, in which he is equally 

 widely read and up-to-date : he includes, for ex- 

 ample, a page on Simpson's results regarding the 

 electricity of rain, and proposes his own inter- 

 pretation of them. The author disagrees with or 

 disparages a large part of the work in meteorology 

 of men like Ferrel and Helmholtz, but there is 



NO. 2285, VOL. 91] 



no evidence of his ability to succeed in solving 

 the problems in which he concludes their woik 

 failed. His book may, however, be very useful 

 for the references which it contains. Many of 

 these are not found in current works, e.g. the 

 reference on p. 11S to Beale's observations of the 

 diurnal variation of the barometer in 1666. 



(4) Prof. Milham has made an excellent plan 

 for his text-book of meteorology. To each 

 chapter is prefixed a table of headings and sub- 

 headings, which indicate the scope of the text : 

 each chapter is followed by sets of questions, of 

 topics for investigation, of practical exercises, and 

 of references to the more recent and directly im- 

 portant works and researches on the special sub- 

 ject of the chapter. The book extends to more 

 than 500 pages of text, in addition to a number of 

 plates reproducing beautiful photographs of 

 clouds, snow-crystals, and other phenomena. It 

 is generally well written and trustworthy, but the 

 author lapses occasionally as when, in describing 

 what the world will be like after the atmosphere 

 has gone and the temperature has fallen below the 

 boiling point of hydrogen, he says : "The constant 

 bombardment by meteors will make life in the 

 open more dangerous than on a modern battle- 

 field." The practical way, in which the United 

 States weather service is regarded, is indicated by 

 the appearance early in the book of "the financial 

 saving caused by the Weather Bureau " as a suit- 

 able subject for investigation. 



The first part of the book deals with meteoro- 

 logy proper, the atmosphere, its constitution, 

 temperature, and circulation, and with weather 

 offices and their work. In the second part the 

 author treats of climate, of atmospheric optics, 

 acoustics, and electricity, and, what is more novel, 

 but of considerable importance, of floods and river 

 stages, their measurement, characteristics, and 

 prediction, the latter forming, in the United States, 

 a part of the regular work of the weather bureau. 



E. G. 



THE HABITABILITY OF THE PLANETS. 



Are the Planets Inhabited? By E. Walter 

 Maunder. Pp. iv+166. (London and New 

 York : Harper and Brothers, 1913.) Price 

 2.S. 6d. net. 



THE question discussed in this little book used 

 formerly to be considered in every popular 

 book on astronomy, and it was generally supposed 

 that all the planets were very probably inhabited 

 by some sort of intelligent beings. The progress of 

 astrophysics has thrown a great deal of light on 

 the physical constitution of the planets, and this 

 excellent summary of modern telescope-work, and 

 of the consequences of the heat and light received 



