64 



measure either a large canal or a stream by means of a miner's inch 

 box, all measurements were made in cul)ic feet per second, according 

 to-modern methods, and afterwards reduced to miner's inches. 



Prior to 1885 Montana had no legal standard for measuring water 

 in motion. In that year the legislature enacted the following some- 

 what imperfect description of a measuring box: 



Sec. 1262. The measurement of water appropriated under this chapter shall be 

 conducted in the following manner: A box or flume shall be constructed with a head 

 gate placed so as to leave an opening of 6 inches between the bottom of the box 

 or flume and the lower edge of the head gate, with a slide to enter at one side of and 

 of suflicient width to close the opening left by the head gate by means of which the 

 dimensions of the opening are to be adjusted. The box or flume shall be placed 

 level and so arranged that the stream in passing through the aperture is not 

 obstructed by back water or an eddy below the gate, but before entering the open- 

 ing to be measured the stream shall l)e brought to an eddy and shall stand 3 inches 

 on the head gate and above the opening. The number of square inches contained 

 in the opening shall be the measure of inches of water. 



For thirteen years the miner's-inch })ox just described was the only 

 legal means of measuring irrigation water, and all court decrees which 

 were rendered from 1885 to the spring of 1898 and which deal with 

 specified volumes of water used in irrigation are expressed in Mon- 

 tana statutory inches. While a new standard unit has been adopted, 

 the old unit can not be said to be wholly abolished. Parties whose 

 rights to the u.se of water were established during this thirteen-year 

 period have been granted the privilege of having the quantity of water 

 to which each is entitled measured by the miner's-inch box." 



Since 1898 the standard unit in Montana for the measurement of 

 water in motion is the cubic foot per second, a cubic foot of water 

 moving at the rate of 1 linear foot in one second of time. In adopting 

 a new standard the members of the Montana legislature foresaw the 

 extended use of the old unit and so defined it in accurate terms. Forty 

 miner's inches are the exact equi\alent of 1 cubic foot per second and 

 the volume of 1 miner's inch is equal to 0.025 cubic foot per second. 



The miner's inch and the cubic foot per second can only be used to 

 measure water in motion. Since it is often convenient to describe a 

 certain quantit}- of w^ater in a state of rest, the acre-foot has been 

 quite generally adopted for this purpose. It means the amount of 

 water that will cover 1 acre to a depth of 1 foot, or 43,560 cubic feet, 

 or 325,851 United States gallons. 



HOW MEASUREMENTS WERE MADE. 



In ascertaining the amount of water applied to individual crops it 

 was customar}" to measure the stream at the upper boundary of the 

 field. This was done in most cases by placing a CipoUetti weir of the 



«See description by author in ^Montana Sta. Bui. 34, p. 4. 



