142 MINING mDUSTEY. 



tically, marking on the circumference tlie starting or zero point. As the cage 

 descends the finger turns on the dial, passing successively the points corre- 

 sponding to the several stations or intermediate places in the shaft. The con- 

 struction of this apparatus is illustrated by Fig. 5 on Plate XIV. S is the 

 main engine-shaft, set in motion by the crank C The pinion, P, drives the 

 spur-wheel, W, by means of which the winding reel, R, is caused to revolve. 

 The relations of the pinion to the spur-wheel being as 1 : 3^, the winding 

 reel, R, makes 100 revolutions for 350 of the engine-shaft. On the latter, 

 near the pinion, P, is fixed a light gear-wheel, g, two feet in diameter, which 

 drives, by means of a similar wheel, g', the countershaft, c. This counter- 

 shaft is provided with a worm, shown at a in elevation, above which is a 

 worm-wheel, b. This is a disk, two feet in diameter, the face or periphery 

 of which is cut to correspond with the worm a, and has 350 threads. As 

 the countershaft, c, and worm, a, revolve with the same speed as that of the 

 engine-shaft, S, the disk, b, is caused to make one complete revolution by 350 

 revolutions of the engine-shaft, 8, equal to 100 revolutions of the winding reel, 

 R. The journal, on which the disk, b, is supported, projects beyond its face, 

 and is provided at h with a pointer, p. The latter revolves with the disk. Be- 

 tween the disk and the pointer a dial, d, is interposed, which is fixed upon an 

 independent support. As the disk is revolved the pointer moves on the face 

 of the dial like a clock-finger, making, as before stated, one entire revolution 

 for 100 turns of the reel on which the cable is wound. Its position, therefore, 

 is always determined by the length of cable that is paid ofi" from the reel. If 

 the position of the pointer be once marked on the circumference of the dial, at 

 points corresponding to any given depth in the mine-shaft, the engine driver 

 can readily see the place of the cage at any moment of its ascent or descent. 



The cages in the shaft are hoisted, lowered, or stopped by the engine 

 driver, in answer to signals communicated to him from below. These are 

 usually given by pulling a bell-wire, hung in the shaft, by means of which a 

 gong or steel triangle, or other similar contrivance, is rung at the surface, the 

 number of strokes indicating whether the cage is to be raised or lowered, or 

 communicating some other necessary intelligence. 



The usual method of conveying these signals is by ordinary iron wire, but 

 it has many disadvantages, arising chiefly from the frequent breaking of the 



