OBSERVATIONS ON THE FALL OF RAIN. 171 
The mean amnual results are— 
Inches. 
At the westerly foot of the hills for 24 years ......... 45 
At the westerly edge of the summit plain, 4 years... 61.7 
Mean of 1840 and 1841............ 67.8 
Easterly edge of do. 1840 and 1841, 2 yrs. 77.45 
Easterly foot, in the Valley 2 years, 40.85 
of the Derwent............ 1840 & 1841 °°" ~* 
The gauges were all exactly alike—all sunk 
into the ground so as to allow the top of the fun- 
nel to be about 12 inches above the surface. 
One very important fact shown by these ob- 
servations, is, that a much greater quantity of 
rain falls on the summit than at the bottom of the 
hills, and this appears to be uniformly the case, 
whether taken for a single month or upon the 
general average. 
The years 1839, 1840, and 1841, were all below 
Dr. Dalton’s average of forty-seven years. 1842 
only gave three-fourths of that average. 
Mr. Thom, of Rothesay, the constructor of the 
Shaw’s water works, near Greenock, and of many 
other similar works in Scotland, has for many 
