MECHANICS AND USEFUL ARTS. 71 



charge of powder placed in the central hole, and the rock within the 

 circular trench will be removed at one blast. One of the arms of the 

 main wheel is made removable, so as to allow a car to pass under the 

 machine to the rock. The fragments broken away by the blast will 

 then be loaded and drawn back to the mouth of the tunnel. The 

 machine is again fed forward and its successive operations will be the 

 same as already described. The main carriage is properly braced so 

 as to be immovable. The weight of the whole machine is from eighty 

 to ninety tons, the weight of the shaft eleven tons, and the weight of 

 the main wheel is thirty tons. It is to be driven by two stationary 

 engines, of forty horse-power each. The designer and inventor of the 

 machine is Charles Wilson, Esq., of Springfield, Mass. 



The practical operation of the machine above described, has not, as 

 yet, been wholly successful. The cutters proved too frail to stand the 

 quartz found in the mica slate, of which the mountain is composed, 

 and were soon broken, and rendered unfit for service. It is proposed 

 to replace these cutters with others of a firmer and more substantial 

 character. The machine has, however, cut into the rock to the depth 

 of about four feet, very smoothly and successfully. The wheel cuts 

 from a 16th to an 8th of an inch at each revolution, and makes five or 

 six revolutions in a minute ; which more than meets the warrant of the 

 builders. The core of the rock is blasted while the machine remains 

 close by, but there is no apprehension that it will be essentially injured 

 by the exploding masses of rock. A difficulty, however, presents 

 itself in the disposal of the rock, after it is cut and blasted out, it being 

 a slow and tedious process to break it and draw it out through the 

 machine. This difficulty will prevent the working of the machine for 

 more than a third or half of the time, all the remainder being occupied 

 in removing the stone. 



We copy from the Scientific American the following notice of a new 

 drilling machine, invented by Mr. C. W. Coe, of Ohio. There are 

 two improvements in this invention. The first has reference to the 

 feeding motion, and also to the mode of raising the drill from the work. 

 The nut which works the feeding screw has on it a pinion capable of 

 gliding up and down, but causing the nut to revolve by means of a 

 groove and feather. This pinion gears into the driving-wheel when 

 at the upper part of the nut ; a rapid motion is then given to the 

 screw, which draws the drill quickly upwards. But when it is desired 

 to give the feeding motion, the pinion is depressed by a lever, and 

 thus released from the teeth of the driving-wheel. The pinion is 

 then moved by two lugs or dogs attached to the inner part of the 

 driving-wheel ; now, if the driving-wheel has a motion given to it the 

 reverse way to that used when raising the drill, it is evident a slow 

 feeding motion will be given to the screw. If desirable, of course, 

 more than the two lugs can be used. 



The second part of the invention embraces a mode of holding the 

 work to be drilled in any oblique direction. A clutch is employed for 

 this purpose of a hollow conical shape, with a screw on the outside 

 this clutch is cut open in a vertical direction, so that if the work be 



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