HOW TO MEASURE MINERS INCHES 



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the capacity of which is known, and which is readily capable of adjust- 

 ment to the flow in any case. A simple form of this device and its 

 use is shown in the illustration, which represents a board 1 inch thick, 

 12 inches wide, and about 8 feet long. The opening is 1 inch wide and 

 50 inches long, and the distance from the top of the board to the center 

 of the opening is exactly 4 inches on the up-stream side. On the 

 down-stream side the opening is beveled so that the hole presents sharp 

 edges to the stream. A sliding board is hung upon the top of the 

 first board, with a strip screwed along its upper edge, this sliding 

 board being wide enough to cover the opening on the up-stream side. 

 In the slot there is a closely-fitting block, made to slide on the beveled 

 edges and fastened by a screw to the sliding board. It is obvious, 



. 'r 



Measuring miner's inches in a small stream or ditch. 



then, that when the sliding board is moved backward or forward, by 

 means of its end, which is extended for a handle, the block moves in 

 the slot and determines the length of the opening. 



In operation the board is placed in the stream as shown in the 

 figure, so as to dam the flow completely, and the sliding board is 

 moved backward and forward until the water is all passing through 

 the slot, the water being kept up to the top of the board, or 4 inches 

 above the center of the opening. The length of the opening measures 

 the number of miner's inches of water flowing through. If the flow 

 is too great to pass through the opening 1 inch wide, the opening may 

 be made wider, the water still to be kept 4 inches above the center of 

 the opening. The laws of several States provide that in devices for 

 measuring water for sale by the miner's inch the opening shall be 6 

 inches high and shall be provided with a slide as shown in the picture. 

 The number of miner's inches then discharged is equal to the number 

 of square inches in the opening. The assumption made that the dis- 

 charge is proportional to the size of the opening is not true, but the 



