174 OBSERVATIONS ON THE FALL OF RAIN. 
reasonable to suppose it must have been a dry 
year also in Scotland; indeed, the returns during 
the summer months show it to have been so. 
In that year, according to Mr. Thom’s return, 
the available rain, or that which was gathered in 
the reservoir in Bute, was to the total fall as 239 
to 454, little more than one half. During the 
six summer months from the beginning of April 
to the end of September, only twelve inches of 
rain fell, being about one-fourth of the whole 
year’s fall. The quantity which drained off was 
to that which fell, only in the proportion of 15 to 
120, just one-eighth. Any calculation upon an 
average during this period would have been 
sorely at fault. 
The following five months were still, probably, 
below an average. The rain in Manchester, ac- 
cording to Dr. Dalton’s tables,* being only 13.535 
inches, while the mean for twenty-two years, in- 
cluding this period, was 15-951 inches, and the 
quantity draining off would be effected by the 
previous drought. The soil must have been far 
* Vide Memoirs of Literary and Philosophical Society 
of Manchester, volume VI., new series, p. 575. 
