METEOROLOGY. 



533 



trie maximum into the region of a dry stationary depression or the pre- 

 cursor of such (especially when the latter lies between the zones of high 

 atmospheric pressure or when the air, blowing out from the maximum, 

 strikes a rising surface of ground) gives occasion for heavy protracted 

 rainfalls. The practical art of weather predictions can sometimes take 

 notice of this correction, even if we are still far from being able to sat- 

 isfactorily explain theoretically the process that goes on." (Z. 0. G. M.i 

 xvii, p. 5.) 



G. Mantel, of Zurich, has studied the distribution of simultaneous rain- 

 falls throughout Switzerland. If over an interval of a days among which 

 there are r days on which more than half of the Swiss stations report 

 rainfall and s days on which more than half the stations show dry weather, 

 then the law of probabilities give us a formula from which to compute 

 how many stations have experienced a simultaneous rainfall. The per- 

 centage of such stations varies from 80 for the winter and spring months 

 to 84.7 for the summer and fall, the average being 82 per cent, for the 

 whole six years ; that is to say, on any day of the year 82 per cent, of 

 the area of Switzerland simultaneously enjoys the same weather, namely, 

 either dry or rainy. Similar computation was made some years ago by 

 Winkelman for Southern Germany, from which seemed to follow that a 

 prediction of uniform weather over either of these portions of Europe is 

 not likely to be verified over more than 85 per cent, of the area. Per- 

 centages greater than 85 are more frequent during dry weather than 

 during rain. (Z. 0. G. M., xvii, p. 377.) 



J. B. Lawes, J. H. Gilbert, and R. Warriugtou have communicated 

 to the Journal of the Royal Agricultural Society of England the results 

 of their observations since 1870 on the amount and composition of rain 

 and drainage waters collected at Rothamsted. These experiments were 

 conducted on a magnificent scale. The drainage is measured by collect- 

 ing-vessels placed 20, 40, and 60 inches below the surface. The general 

 average is shown in the following table : 



It is not clear why the 40-inch drain should, during 1875-'80, have 

 collected more than the 20 or 60 inch drains. The greatest drainage 

 occurs in autumn and winter when the evaporation is a minimum. (Z. 

 O. G. M., xvn, 446.) 



Symons quotes the following as the best results of the studies of 

 Phillips, Bach, Jevons, Dines, Field, and others, into the diminution of 



