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THE AMERICAN NATURALIST [Vol. LI 



a. The relationship between the number of sunspots and the 

 annual record of terrestrial meteorological phenomena is very 

 slender indeed. It is so slight that at the present time it is im- 

 possible to assert on the basis of the data of any one station alone 

 that any relationship at all exists. Thus, as far as they go, these 

 data hold out very little hope to the biologist of being able to 

 correlate plant activities with sunspot number, unless light in- 

 tensity be the means of solar influence. 



h. For rainfall and barometric pressure the correlations are 

 especially low. They average practically zero, but are apparently 

 on the whole negative in sign. 



c. The correlation between number of sunspots and terrestrial 

 temperature is the most consistent and substantial of the three. 

 The coefficients average about — .14. Thus years of larger num- 

 bers of sunspots are in the long run years of lower, not higher, 

 terrestrial temperature.^ 



These results are directly opposed to the theories which seem 

 to have prevailed among many writers. 



J. Arthur Harris 



5 Possibly, as Walker suggests, superheating in equatorial regions may 

 raise the temperature in the upper air but lower that at ground level. The 

 temperatures in which the botanist is primarily interested are, however, 

 those which may influence the film of vegetation which covers the globe. 



