1873.] between Rainfall and Sun-spot Periodicity, 301 



periods of three years each, and, which is still more striking, that the ex- 

 cess is on the side of the maxima-periods at fifteen out of the eighteen 

 stations. 



In the last three columns I have given the total rainfall for the single 

 maxima-years 1817, 1830, 1837, 1849, and 1860, and for the single 

 minima-years 1823, 1834, 1844, 1856, and 1857, with the excesses and 

 defects ; and we find a total excess of 105*36 inches in favour of the 

 maxima-years, only five stations showing an excess on the other side. 



The unfavourable stations are Toronto, Calcutta, and Natal ; and it 

 should be remarked that at Toronto the snow was not melted, but one 

 tenth of its depth taken to represent an equivalent depth of water, while 

 Mr. Blarifone, the meteorological reporter to the Bengal Government, 

 has expressed a doubt as to the accuracy of the Calcutta observations in 

 the earlier part of the series. If, however, we had taken the years 1847-49 

 in place of 1848-50 for the maximum-period, the Calcutta observa- 

 tions would have given a different result. "With regard to Natal, the 

 geographical peculiarities described by Dr. Mann probably render that 

 station unfavourable for showing in a few years any periodicity that may 

 exist. 



Having ascertained, then, that there is at nearly all the above stations 

 a very remarkable difference in the amount of rainfall at or near the 

 turning-points of the sun-spot period, the next step is to find the effect 

 of grouping the observations. Tor this purpose we give, in the first 

 place, the rainfall. at as many stations as possible in each minimum-sun- 

 spot year, and in each two or three years on either side of it ; and, in the 

 second place, we give the rainfall for each maximum-year and two or 

 three years on either side of it. If we do not find any tendency to 

 an equalization of the annual rainfall, we shall have further proof of a 

 periodicity. 



Table III. (Minimum-year, 1834). 



Stations. 



1831. 



1832. 





1834. 



i'835. 



1836. 





in. 



in. 



in. 



in. 



in. 



in. 





29-16 



21*07 



22*04 



1228 



14-94 



2469 



Carbeth 



49*59 



40-29 



46-12 



42*37 



42-60 



53*9° 





34'4- 8 



30*69 



29-79 



23-84 



29*21 



31-01 



Total 



113-23 



92-05 



97*95 



78-49 



8675 



109-60 





3474 



30-68 



32*65 



26-16 



28-92 



3^*53 



The above Table shows no tendency to an equalization, but to the 

 formation of a curve, the lowest point of which corresponds with the 

 minimum-sunspot year. 



