THE COMSTOCK MINES. 141 



long, 4 feet in diameter, containing 50 tubes of 3 inches diameter. They 

 consmne about 8 cords of wood per day. 



The three hoisting engines stand side by side, and are so placed that the 

 winding reel, operated by each engine, is directly opposite the compartment 

 for which it is designed. Each engine, with its winding apparatus, is inde- 

 pendent of the others. 



The winding apparatus, connected with each engine, consists of a reel, 

 similar in construction to that shown in Fig. 1, Plate XIV. The reel is keyed 

 to a shaft 7 inches in diameter, which is driven by a spur-wheel 10 feet in 

 diameter; the latter is moved by a geared pinion on the engine shaft. The 

 relative diameters of the spur-wheel and pinion are as 3^ : 1. 



The cable is made of steel wire. It is flat, 4^ inches wide by f of an 

 inch thick. It is of the best English manufacture, and is said to withstand a 

 breaking strain 30 per cent, greater than cables of iron wire, which are twice 

 as thick. One great advantage of the steel over iron band is its slight thick- 

 ness, which allows of winding a much greater length of band on a reel of 

 given diameter, consequently reaching a greater depth without change of 

 winding gear. The reels now in use have a capacity of 1,200 feet of rope. 



The average speed of hoisting the cage in the shaft is about 400 feet 

 per minute. 



The engine driver, engaged in hoisting, stands by his machine, controll- 

 ing the throttle-valve by one hand, the reversing-bar with the other, and a 

 brake with one foot. The brake is applied to the fly-wheel of the engine, 

 and is sufficiently powerful to hold a loaded cage. The winding apparatus 

 being geared, and the spur-wheel keyed to its shaft, the engine is always re- 

 versed for lowering the cage, which operation may be managed by the brake 

 on the fly-wheel, or controlled by a pressure of steam. 



The position of the cage in the shaft, at any moment of its ascent or de- 

 scent, is shown to the operator by an "indicator," connected with the wind- 

 ing machinery, and in full view of the engine driver. 



The indicator used at the Savage mine consists of a circular plate or 

 dial, about the center of which a pointer, like the finger of a clock, revolves, 

 showing, by means of points marked upon the circumference, the position of 

 the cage in the shaft. When the cage is at the surface the finger stands ver- 



