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fice is 2 inches high and its length adjustable by a slide. The center of the 

 orifice is 8 inches from the top of the board, the lower edge of the orifice is 

 6 inches above the floor. The edges of the orifice are bevelled on the down- 

 stream side. The slide consists of a 1 in. x 6 in. piece which passes through 

 a hole of the same size cut through the side of the box. At one end of this 

 piece is screwed a short block which fits into the bevelled orifice and which 

 has one edge bevelled to conform with the other edges of the orifice. To 

 measure the water the slide is pushed in or pulled out until the water 

 stands level with the top of the board; when the slide is pushed in too far 

 the water overflows the top of the board; when the orifice is opened too 

 wide, the water level drops below the top. The number of miners' inches 

 passing through is equal to the length of the orifice multiplied by two. To 

 facilitate the measurements the orifice may be graduated with inch and 

 quarter inch marks, each half inch representing a flow of 1 miners' inch. 



Fig. 15 Miners' inch measuring box. 



