167 
PHYSICAL AND MATHEMATICAL SECTION. 
April 28th, 1874. 
Alfred Brothers, F.R.A.S., President of the Section, in 
the Chair. 
''On the Ratios and Frequency of Rainfall, deduced from 
Observations made at Eccles,” by Thomas Mackereth, 
F.R.A.S., F,M.S. 
A few weeks ago Thomas Glazebrook Ry lands, Esq., of 
Th el wall, near Warrington, was kind enough to draw my 
attention to the amount of rainfall at that place for the 
years 1872 and 1873. The amount which fell there in 
1872 was 47*52 inches, and in 1873 it was 24*53 inches. 
These amounts Mr. Rylands considers extremes of rainfall 
for that district, and he was led to make several comparisons 
between them. The results of these comparisons show 
curiously enough that "the amount of excess in rainfall 
increases with the amount of rain, and therefore that the 
increase is due mainly to the maximum falls.’' 
In putting the falls of the two years mentioned into 
ratio they stand thus, 1*940:1. But the number of days 
of rainfall in the two years stand thus, 1.235 : 1. Mr. 
Rylands then introduces into comparison the ratios that 
exist between other elements; but as those results only 
apply to his own register, I will not now mention them. I 
will merely state, having mentioned the rainfall for the two 
years at that place, that the number of days on which rain 
fell there in 1872 was 233, whilst in 1873 the number of 
days was 189. But if the number of days on which rain 
falls in a wet year is to bear any comparison with those of 
a dry year the result must be very different, for the ratio 
