322 



KEPORT ON NATIONAL MUSEUM, 1886. 



.'irraugeuicut, awaj^ from the center. The drill, lifted, drops with great 

 force and rapidly creases a channel into the rock. The single-gang 

 machine is operated by two men, the double by three. As it runsback- 

 NYard and forward over the rock the machine is reversed without stop- 

 ping, and as it goes the cutters deliver their strokes, it is claimed, at 

 the rate of one hundred and fifty per minute. The machine feeds for- 

 ward on the track half an inch at each stroke, cutting half an inch or 

 more every time of passing. The single machine will cut from 40 to 80 

 square feet of chnnnel per day in marble or limestone and at a cose of 

 from 5 to 20 cents per square foot. The double machine will do twice 

 the amount of work. A good workman would formerly cut from 5 to 10 

 feet, that is, a groove 1 foot deep and from 5 to 10 feet long per day. 



Saunders Channoliiig Machine with boiler attached. 



For this he would receive from 25 to 30 cents per foot.* Another ma- 

 chine for doing the same work as that just described is the Saunders 

 channeling machine shown in the illustration, and which has recently 

 come into use in the Vermont quarries. This differs from the Wardwell 

 in several important particulars, prominent among which are these: (1) 

 The cutting tool is attached rigidly to the piston, so that the blow is 

 dealt directly by the steam pressure in the cylinder and without the 

 intervention of any cranks, levers, or springs. (2) The cutting tools are 



* The Marble Border of Westera New Euglaud, p. 43. 



