110 IRRIGATION FARMING. 



Colorado. A quantity of water equivalent to a contin- 

 uous flow o one cubic foot a second, during the irrigat- 

 ing season of one hundred days, will usually irrigate 

 from fifty to sixty acres of land. It will often do more 

 than this. Another unit still generally employed in the 

 West is the miners inch. This differs greatly in differ- 

 ent localities and is generally defined by state statute. In 

 California one second foot of water is equal to 50 miner's 

 inches, while in Colorado it is equivalent to 38.4 miner's 

 inches. In the following arrangement are given a few 

 convertible units of measure : 



1 second foot=450 gallons a minute. 



1 cubic foot=:75 gallons a minute. 



1 second foot=2 acre feet in 24 hours approximated. 



100 California inehes=4 acre feet in 24 hours. 



100 Colorado iuches=5 1 , acre feet in 24 hours. 



1 Colorado inch=r!7,000 gallons in 24 hours. 



1 second foot=59Va acre feet in 30 days. 



2 acre feet=l second foot a day or .0333 second feet in 30 days. 



A miner's inch is supposed to define the quantity of 

 water flowing through an aperture an inch square, but as 

 in some parts the pressure adopted is that of a four-inch 

 head, while in other places the head is six inches, there 

 is evidently abundant room for variation, even in the 

 determination of the capacity of a single inch. When 

 again a number of inches came to be measured at once 

 it became possible either to adopt an aperture one inch 

 high and the specified number of inches in length, or to 

 take the square of the whole number of inches as giving 

 the dimensions of the orifice, in which case there is an- 

 other great cause of variation. The State Engineer of 

 Colorado has calculated that the miner's inch has been 

 .026 cubic feet, or, roughly speaking, a fortieth of a 

 cubic foot, which is equivalent to a flow of nearly nine 

 gallons a minute, and this is now generally adopted, 

 though as a matter of fact, in more southerly states 

 where water has been scarce, the miner's inch has only 

 meant one fiftieth of a cubic foot. 



