744 



SCIENCE. 



[N. S. Vol. IX. No. 230, 



tion, force and velocity of the wind are fully- 

 explained, but it is not until the author reaches 

 the subject of the causes of the wind, and its re- 

 lations with the temperature and pressure, that 

 the reader's greatest interest is aroused. For 

 it is here that the modern aspect of meteorology 

 really begins, and it is just here that the author 

 encounters his greatest difficulties. He gives 

 first the cause and maintenance of fluid motions 

 as depending on the differences of pressure at 

 the same level, and establishes the complete 

 circuit of such movements of the air ; he then 

 proceeds to explain the meaning of the terms 

 isobaric lines and harometric gradients. Then 

 follow, in succession, the influence of the earth's 

 rotation on the movements of the air, the curve 

 of inertia, the formation of cyclonic and anti- 

 cyclonic whirls, aud the circulation of the air 

 around centers of warm or cold air. After this 

 comes the general circulation of the atmosphere; 

 the constant winds, the ' Trades ;' the seasonal 

 winds, the monsoons ; the diurnal winds, the 

 land and sea breezes, mountain winds, etc. 



I must confess to a feeling of disappointment 

 upon reading this part of Professor Angot's 

 book. I had hoped that he would have given 

 us a simple, clear, logical development of the 

 air circulation somewhat after the manner of 

 Ferrel's theory, but which should include the 

 views of the best European investigators. That 

 is what we need ; but the author has contented 

 himself with the older method of a disconnected 

 treatment of the different features of the at- 

 mospheric circulation, some of which have been 

 treated in one way and some in other ways by 

 the various investigators who first developed 

 them. I think that all of those who have tried 

 to present in an elementary manner the results 

 of the later investigators concerning the ' cir- 

 culation of the atmosphere' have attempted an 

 impossible short cut in meteorological litera- 

 ture, and that there must first be written an 

 advanced treatment of the subject, which can 

 later be simplified for an elementary treatise. 

 Until this elaborate treatise has been written I 

 think that Ferrel's development of the subject 

 as given in his ' Popular Treatise of the Winds' 

 (New York, 1889) will still remain the best for 

 presentation to the student or general reader. 

 We must bear in mind that Ferrel preceded 



this popular exposition of the subject by his 

 highly technical ' Recent Advances in Meteor- 

 ology.' 



In Angot's chapter on atmospheric humidity 

 the sections on condensation and clouds deserve 

 special mention, and the reproduction of cloud 

 photographs are unusually good. Under rain- 

 fall the charts showing the continental distribu- 

 tion of this element are valuable. 



The subject of meteorological optics is really 

 too difiBcult for presentation in a very elemen- 

 tary treatise on meteorology, but the author 

 has succeeded rather better than is usual in his 

 brief treatment of the subject. 



The development of the subject of cyclones, 

 thunder-squalls and spout phenomena is very 

 full ; but Faye's theories are given perhaps un- 

 due prominence from the German and Ameri- 

 can points of view. 



In this, as in other recent treatises, the sub- 

 ject of Weather Predictions has not the space 

 devoted to it which its practical importance 

 demands. 



The last chapter takes up briefly the meteor- 

 ological periods or cycles, and cosmic influ- 

 ences. 



Taking Angot's book as a whole, there is a 

 deliberateness of treatment of each topic which 

 can only be attained either by the making of a 

 bulky volume or the exclusion of many impor- 

 tant topics which deserve mention ; and in the 

 reviewer's opinion the use of the work as a text- 

 book will be lessened thereby, but its value to- 

 the general reader will be increased. The lack 

 of an index is, however, a most serious draw- 

 back to the free use of the book as a work of 

 reference, for it requires the knowledge of a 

 specialist to be able to turn at once to minor 

 topics by the aid of the rather full table of con- 

 tents alone. 



Professor Angot's 'Meteorology' is a much 

 more important contribution to French litera- 

 ture than it is to the world's literature of the 

 subject, and it will, undoubtedly, do a great 

 amount of good in supplying French readers 

 with information concerning the present con- 

 dition of a subject of very rapidly increasing 

 interest. The French meteorological literature 

 of recent years has not been nearly as abundant 

 as that of other countries, and we trust that 



