THE COMSTOCK MINES. 119 



to these "safety cages" differ a good deal in detail of construction, and, prob- 

 ably, in degree of efficiency, but they generally depend on a spring so fixed, 

 with regard to the rod by which the cage is attached to the cable, as to be 

 compressed while the weight of the cage exerts any strain upon the cable ; 

 but if that strain is relaxed by the breaking of the cable or other parts of the 

 winding machinery the spring is permitted to act upon some mechanical con- 

 trivance by means of which stout iron teeth are forcibly projected against, or 

 caused to grasp, the guides along which the cage is moved. These teeth are 

 so arranged that when the spring is compressed they move along the guide 

 without coming into contact with it, but when the spring is relieved act with 

 the greater force the heavier the load on the cage. 



The contrivance on the cages used at the Savage mine may be seen in 

 the drawings on Plate VII. A horizontal movable bar of iron, h, Fig. 1, 

 crosses the cage near the top, from side to side. The lifting-rod, r, by which 

 the cage is attached to the cable, passes through this bar and is so connected 

 with it that the latter may move upward and downward between guides, g, g, 

 according as the rod is raised or suffered to fall. When the rod is raised by 

 the strain of the cage on the cable the bar is elevated, but if the strain on 

 the cable is relaxed, the rod consequently falling, the bar moves downward 

 and a strong spring, s, is introduced to force it down whenever this condition 

 occurs. To each end of this cross-bar, on opposite sides of the cage, is 

 attached at right angles a shorter horizontal bar, c, Fig. 2. To each extremity 

 of each of these last-named bars, c, c, is attached one end of a system of levers 

 by means of which two stout iron teeth or "dogs," t, t, at the other end, are 

 thrown against the guide-rods in the shaft when the cross-bar is down, or 

 drawn from the guide-rods when the cross-bar is raised. 



In Fig. 2 this contrivance is shown in such manner that the action of 

 the levers can be readily traced. The cage not being suspended by the 

 cable the cross-bar is depressed and the teeth are almost in contact with each 

 other, in the position in which they would grasp the wooden guide-rods were 

 the cage in the shaft without its usual support. The dotted lines indicate the 

 position of the levers and teeth when the cage is hanging on the cable and 

 the cross-bar, b, is raised. 



This kind of safety catch has been proved to be very efficient. In the 



