. Report of the Geological exploration of the fortieth parallel . f7 feet, under ordinary circumstances, about four times per minute, thoughcapable of much higher duty, if required. The bob is of wrought and cast iron combined. The pump-rod is madeof pine, in sections 30 feet long and 12 inches square, joined together asalready described. The weight of the rod, with its iron straps, is partly bal-anced by the counter-weight on the bob at the surface, besides which thereare three balance bobs at stations below ground. The pumps have beenalready described. The plungers are 10 and 12 inches in di
. Report of the Geological exploration of the fortieth parallel . f7 feet, under ordinary circumstances, about four times per minute, thoughcapable of much higher duty, if required. The bob is of wrought and cast iron combined. The pump-rod is madeof pine, in sections 30 feet long and 12 inches square, joined together asalready described. The weight of the rod, with its iron straps, is partly bal-anced by the counter-weight on the bob at the surface, besides which thereare three balance bobs at stations below ground. The pumps have beenalready described. The plungers are 10 and 12 inches in diameter. Thecolumn of elevation is 14 inches. There are three hoisting engines, one for each compartment of the are 16-inch horizontal cylinders, having 36 inches length of stroke, andare fitted with slide valves and link motion. Three boilers furnish steam to all these engines. They are set in theadjoining boiler-room, partly shown in the drawing. They are each 16 feet Plate X^■ •frerii- fa Tunbn- Yar<l aiiorxn ilax or AT Tin-:SAVAGE .\II.\J-:. THE COMSTOCK MINES. 141 long, 4 feet in diameter, containing 50 tubes of 3 inches diameter. Theyconsmne about 8 cords of wood per day. The three hoisting engines stand side by side, and are so placed that thewinding reel, operated by each engine, is directly opposite the compartmentfor 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 keyedto a shaft 7 inches in diameter, which is driven by a spur-wheel 10 feet indiameter; the latter is moved by a geared pinion on the engine shaft. Therelative 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 aninch thick. It is of the best English manufacture, and is said to withstand abreaking strain 30 per cent, greater than cable
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Keywords: ., booksubjectbotany, booksubjectgeology, booksubjectpaleontology
