No. 612] 



NOTES AND LITERATURE 



763 



lie between -\- .10 and — .10. The probable errors of the con- 

 stants are of about this magnitude. 



The average values of the three sets of correlations are : 

 For sunspots and rainfall, 151 stations, r = — .0175 

 For sunspots and temperature, 97 stations, r = — .1360 

 For sunspots and pressure, 91 stations, r = — .0331 



While these averages are exceedingly small, all are negative in 

 sign, indicating that for the globe as a whole lower rainfall, tem- 

 perature and barometric pressure are associated with greater 

 numbers of sunspots. 



The same relationship is apparent if only the 76 stations for 

 which all three relationships have been calculated be considered. 

 The averages are : 



For sunspots and rainfall, r = — .0349 



For sunspots and temperature, r = — .1534 

 For sunspots and pressure, r = — .0486 



If in obtaining the average correlations the constants for the 

 several stations are w^eighted with the number of years for which 

 records are available the averages, indicated by the bars, are : 

 For sunspots and rainfall, 151 stations, r = — .0103 

 For sunspots and temperature, 97 stations, r = — .1243 

 For sunspots and pressure, 91 stations, r = — .0387 



Thus, however calculated, the averages indicate generally 

 negative values of the correlation coefficient for all three rela- 

 tionships. 



The same fact is brought out if the coefficients are classified 

 according to sign only. Thus : 



For all three relationships the negative correlations are more 

 numerous than those which are positive in sign. 



In a brief review it is quit€ impossible to give in detail the 

 meteorological considerations discussed in the original memoirs. 

 Furthermore, the most of these do not directly concern the botan- 

 ist. The conclusions of practical biological importance to be 

 drawn from "Walker's investigations seem to be the following: 



