136 MINING INDUSTEY. 



and driven by a pinion which is keyed to the engine-shaft, so that the reel 

 must always have a motion corresponding to that of the engine, and cannot, 

 as is practicable in some other methods of arrangement, be reversed, for low- 

 ering the cage, unless the engine be reversed also. In the Savage works, 

 shown on Plate XV, there is a separate engine and independent winding gear 

 for each hoisting compartment of the mine-shaft ; and so arranged that each 

 engine is connected with but one reel and cannot work either of the others. 

 In this arrangement the practice, sometimes desirable, of hoisting one cage 

 as the other descends, in such manner as to allow the descending cage and 

 rope to counterbalance the ascending, is impossible. 



Another method, similar to the above in some respects, but possessing 

 important modifications, is that which is in use at the Crown Point works, 

 shown on Plate XII. In this case there are two winding spools or drums, A 

 and B, one for each hoisting compartment. There are also two hoisting 

 engines, C and D, each of which, under ordinary circumstances, is used for 

 a single compartment. Each spool, with its spur-wheel, is keyed to a spool- 

 shaft and driven by a pinion, which is keyed to the engine-shaft The engine 

 must therefore be reversed, as in the case of the Savage, in order to reverse 

 the motion of the spool ; but the engine-shaft of either engine is long 

 enough to control both spools and each shaft is provided with two pinions, 

 one for each spool. Under ordinary circumstances, the machinery is ar- 

 ranged as shown in the drawing. The engine on the right, C, drives the 

 spool A, nearest to it, by the pinion E, the pinion F for the remote spool B, 

 being thrown out of gear ; while the engine on the left, D, drives the remote 

 spool B, by the pinion H, the pinion G, for the nearer spool A, being thrown 

 out of gear. In case of accident to one engine, the other can work either 

 spool ; or, by throwing out of gear both pinions of one engine, and putting 

 in gear both pinions of the other engine, both spools may be driven at the 

 same moment, one hoisting and the other lowering a cage. In this case, of 

 course, the two ropes or cables must be wound upon the spools in opposite 

 directions. There are no brakes on these spools ; but one is applied to the 

 fly-wheel of each engine. The pumping engine, P, in the case illustrated, 

 has no connection with the hoisting gear, and is devoted exclusively to driv- 

 ing the pump by means of the pinion, J, and wheel, K, as shown in the draw- 



