104 
that for the years 1862-4 amounts to 1*95. It appears there- 
fore that the calorific intensity of the sun’s rays continued 
to diminish for two years after the termination of the Oxford 
series, and as the observations of Schwabe, Wolf, Balfour 
Stewart, and others, have shown that the frequency of solar 
spots also diminished during these two years the probability 
that a close connexion exists between the two phenomena is 
considerably increased by the results of Mr. Mackereth’s 
short but valuable series of observations. 
On comparing the Oxford and the Eccles series of results 
it will be seen that the values for the years which are com- 
mon to both (1862-4) are greater at Eccles than at Oxford 
in the ratio of 1 ‘17 to 1‘00, thus indicating that the blackened 
bulb of the thermometer at Eccles absorbs radiant heat more 
readily than that at Oxford. Dividing the Eccles mean 
annual values by 117 in order to reduce them to the Oxford 
scale and recalculating the ratios we have 
Reduced Values 
of Solar Radiation. 
) 
Ratios. 
1862 
9-33 
1-82 
1863 
9-82 
1‘63 
1864 
9-84 
1-51 
1865 
8-32 
1-57 
1866 
7‘06 
117 
Combining now the two series of ratios, and taking the 
means of the two values given for each of the three years 
1862-4, we have finally, the following series of corrected 
ratios all referred to the same scale, and therefore strictly com- 
parable with each other. I have added for comparison the 
