THE COMSTOCK MINES. 131 



steadily employed, even on comparatively little water, but working on short 

 stroke and at low speed. In others they are idle during a great part of the 

 day, and in some, among them some of the deepest works on the lode, the 

 ground has been almost entirely without water. 



Ventilation. — During the earlier years of work on the Comstock lode 

 little or no difficulty was experienced in effecting free ventilation of the 

 mines, the underground works, even to considerable depths, being in commu- 

 nication with the surface either by adits or connected shafts in such manner 

 as to insure an easy circulation of air. 



As the depth increased and work had to be done at points not reached 

 by the ordinary circulating currents of air in the mine, various simple and 

 well-known means were employed to supply fresh air to the laborers. One 

 of the simplest and most efficient appliances for that purpose formerly used 

 in the Gould and Curry was the water blast, consisting of a wooden box-pipe, 

 P, Fig. 4, Plate VI, standing in the shaft some 200 feet high, and connected 

 at the bottom with an air pipe, A. In the case illustrated, the standing pipe 

 extended from the fourth station down to the sixth, at which point an explor- 

 ing drift was being carried eastward several hundred feet. The object of the 

 blast was to supply air to the laborers in the end of this drift. The top of 

 the box pipe, P, is open, and a finely divided stream or shower of water being 

 caused to fall into the box carries down with it a volume of air. The bottom 

 of the pipe, P, dips into a box, B, 2 or 3 feet long and 15 inches deep, in 

 which the water is allowed to stand above the bottom of the pipe, and from 

 which the excess escapes, through a sliding gate or valve, v. Con- 

 nected with the water pipe just above the box, B, is the air pipe, yi, lead- 

 ing to the point to which fresh air is to be forced. The air coming down the 

 standing pipe, P, with the water, and having no other means of escape, is 

 driven along the horizontal air pipe, A, and delivered at the desired point. 



Latterly the deeper mines have found the lack of good air and the greatly 

 increased heat sources of much trouble, and some of them have been forced 

 to resort to more costly means of ventilation. For this purpose the method 

 generally in use at present is that of forcing air down the mine and into the 

 several levels or tunnels, where it is most needed, by means of a Root's 

 Blower. This machine, well known for purposes of the kind, has been found 



