THE COMSTOCK MINES. 133 



The method of drawing the foul or heated air from the mine by means 

 of the blower and allowing fresh air to take its place by entering the shaft, a 

 plan used elsewhere and much preferred by some, has not been tried on the 

 Corastock, so far as the writer is informed. If readily practicable it would 

 probably furnish better and cooler air throughout the mine generally than is 

 furnished by the means now in use. In the Crown Point mine the 1,100-foot 

 level, at the time of the writer's last visit, was insufferably hot throughout 

 almost its entire length ; the air being cool and fresh only at the extreme end 

 of the pipe and becoming heated immediately after its exit. 



Hoisting and Pumping Woeks. — The hoisting and pumping works on 

 the Comstock lode are among the best of their kind in the country. As most 

 of the claims located on the vein are short in extent, few of the companies 

 have more than one working shaft, and in some cases, as in that of the 

 Empire-Imperial and neighboring short claims, a number of companies have 

 combined in sinking one shaft for their common use. The principal shafts of 

 the leading companies of the present day are generally established on a 

 liberal scale, designed for permanent and deep workings and furnished with 

 pumping and hoisting machinery of the most substantial and effective sort. 

 These surface works are located directly at the mouth of the shaft, and are 

 usually well inclosed by large and conveniently arranged buildings, connected 

 with which are the various shops for all necessary auxiliary work, such as 

 carpentry, smith work, and general repair. 



The engines employed for hoisting and pumping are, in most cases, 

 horizontal, non-condensing engines. Sometimes one engine performs the 

 v/hole duty of pumping and hoisting, but in the larger mines, it is customary 

 to provide one engine for pumping only, and one or more for hoisting rock and 

 ore. 



In hoisting apparatus, the winding reels or drums are operated either by 

 cog or friction-gearing. The latter was much used a few years ago, but as 

 the depth of the mines has increased it has been abandoned by some and 

 replaced by cog-gearing, which is thought safer and more effective for deep 

 works. 



The kind of friction-gear formerly in general use is that known as the V- 

 wheel and pinion, the construction of which is shown, in detail, in Fig. 2, Plate 



