OBSERVATIONS ON THE FALL OF RAIN. 177 
Some useful information may be obtained from 
observations, which have been made upon the 
quantity of water discharged from the Turton 
and Entwistle reservoir, near Bolton. This is a 
large reservoir, containing about one hundred 
millions cubic feet of water, constructed about 
the years 1835 and 6, for the purpose of regulat- 
ing the supply of water on Bradshaw brook and 
the river Irwell, by impounding the flood waters. 
Mr. Thomas Ashworth, was the engineer em- 
ployed to construct it. Having fixed an iron 
gauge below the outlet from the reservoir, all the 
water discharged was for sometime regularly 
measured, none being permitted to flow away, 
otherwise than through the gauge. 
In his printed report to the commissioners of 
the reservoir, dated Sepember 12th, 1836, he 
states, that the quantity discharged during the 
first year, amounted to 250,865,600 cubic feet, 
and that there was then in the reservoir a depth 
of water of seventy-two feet, which, according to 
his estimate of the capacity, may be taken at 
about 50,000,000 cubic feet. 
The drainage ground, carefully measured from 
