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Vercelli, of Milan. There are few references to really recent work, and the 

 names of Bjerknes, Shaw, and W. H. Dines, for instance, do not once occur 

 even in the chapter devoted to the exploration of the upper atmosphere. 



E. V. N. 



Clouds : A Descriptive Illustrated Guide-book to the Observation and 

 Classification of Clouds. By Geo. Aubourne Clarke, F.R.P.S., 

 F.R.Met.Soc. [Pp. xvi + 136, with 70 plates and 17 figures.] (Lon- 

 don : Constable & Co., 1920. Price 21s. net.) 

 Mr. Clarke has divided his book into two parts. In the first he outlines the 

 international classification of clouds, and in a chapter entitled " Cloud 

 Forms and Transformations " discusses the different forms in detail. Among 

 many other interesting observations those relating to lenticular clouds are of 

 especial interest. These clouds occur very often at Aberdeen with south-west 

 winds, and rather less often with westerly winds — that is to say, in winds that 

 have crossed the mountains. This is in agreement with observations abroad, 

 and also in this country Capt. C. J. P. Cave has found that at Ditcham Park 

 they accompany north-west winds that have crossed the South Downs, At 

 Aberdeen the accompanying south-west wind has the characteristics of a fohn 

 wind developed on a small scale. In dealing with cumulo-nimbus clouds it 

 is observed that at Aberdeen a sub-type is of frequent occurrence in which 

 the anvil-shaped extension of false cirrus is so well developed that the cloud 

 sometimes consists of little else. Such clouds are seen in boisterous weather 

 with northerly winds, and from them fall frequent showers of rain, hail, or 

 sleet. Stratus clouds persist over Aberdeen for days at a time as unbroken 

 grey sheets, often accompanied by exceptionally good visibility underneath. 

 It would be interesting to have the author's explanation of this, for an inver- 

 sion of temperature, or at least a region of small lapse rate, would be expected 

 at a moderate elevation with these clouds, and this would hinder the removal 

 of dust particles by convectional currents from the air near the ground, and 

 would tend to produce poor visibility. 



The second part of the book is the most valuable, but does not lend itself to 

 discussion, for it consists of a large selection of excellent cloud forms, abun- 

 dantly illustrating each type. It cannot be too strongly recommended, to 

 professional and amateur alike. E. V. N. 



Meteorology : An Introductory Treatise. By A. E. M. Geddes, D.Sc, O.B.E., 

 M.A. [Pp. XX + 390, with 20 plates and 103 diagrams.] (London : 

 Blackie & Sons, 1921. Price 21s. net.) 

 Mr. Geddes' book is very welcome, as no comprehensive text-book of Meteor- 

 ology has been produced in this country in recent years which could be regarded 

 as a standard work for the non-mathematical student. No aspect of modern 

 meteorology can be said to have been neglected in this work, but it is unfor- 

 tunate that in the section devoted to weather forecasting the novel theories of 

 Professor Bjerknes and the enterprising experiments of the Norwegian 

 Meteorological Service receive no mention, but this could hardly have been 

 avoided without delaying the publication of the book. It is gratifying to 

 note that atmospheric electricity receives so much attention, as it is not 

 easy to keep in touch with this somewhat specialised branch of meteorology. 

 It is to the advantage of the book that the author seeks to express rather the 

 views of English meteorologists as a whole than to advance particular 

 theories. The style throughout is easy and attractive, and the reader is not 

 obliged to have already a knowledge of physics in order to follow the reason- 

 ing. For the majority of the fine illustrations the author is indebted to his 

 fellow-citizen, Mr. G. A. Clarke, who has done so much to stimulate the 

 study of clouds and the direct visual observation of the weather. 



E. V. N. 



