L 



166 PROF. B. STEWART ON THE LONG-PERIOD 



Proportional Rainfall-inequality, as exhibited by series 

 of years. 



Eight Nine Ten Eleven Twelve Thirteen Fourteen 



years, years, years, years, years. years, years. 

 English rainfall, 1 



Symons'sCata- I 2'63 I'l/^ i'55 179 3"i5 rSi) z'^j 



logue J 



Paris 2'68 3-07 i'99 2*65 370 2*57 3*08 



Padua 177 3'6a 2*02 i'47 3"3i 3'52 3-40 



Milan i'i2 3-22 3'i6 178 4"i3 378 a'49 



We ought to give the English, the Paris, and the Padua 



observations a somewhat higher weight than those of 



Milan, as the former embrace a longer period. This will 



be done sufficiently well by giving the first three sets 



weights of 3 each and the Milan set a weight of 2. If we 



perform this operation and then take the mean, we obtain 



as under : — 



Eight Nine Ten Eleven Twelve Thirteen Fourteen 

 years, years, years, years, years. years, years. 

 Mean of the four "I 

 stations, weight- i- z'l^ J'oo 2-09 f94 3*52 2'8i 2*92 

 ed as above ... J 



A maximum corresponding to nine years, and a still greater 

 one, corresponding to twelve years, are thus exhibited, each 

 of these being recorded at three stations out of four. 



The proportional numbers indicated are not large ; but 

 it must be remembered that it is the mean diflPerence for 

 all the years that is given, and that the maximum and 

 minimum rainfall will represent diflFerences above and 

 below the mean which will each be about double the num- 

 bers recorded above. 



10. E/Cgarding the rainfall-values as representing the 

 meteorological result of the sun's action, let us now com- 

 pare these with declination -range values, which may be 

 taken to represent the sun^s magnetic effect. Professor 

 Loomis has compiled (American Journal of Science and 



