I 



THE COMSTOCK MINES. 145 



The apparatus at the signal stations in the shaft consists of a small box, 

 in which two smaller but similar coils are placed, as in the gong boxes at the 

 surface, just referred to. Two upright metallic pieces pass from the coils to 

 the outside of the box, one of which, receiving the end of the shaft conduct- 

 ing wire, is in direct connection with the coils ; the other upright, receiving 

 the end of the ground wire, is not directly attached to the coils, but is so 

 placed that a slight movement of a metallic spring is necessary to complete 

 the connection. The spring, if drawn down, as it may be by hand, makes 

 the circuit complete, and, when released, breaks it again immediately. The 

 coils in this box are not essential, it only being necessary to connect the two 

 wires, or the shaft conductor and the ground wire ; they are only introduced 

 to act as a magnet on another gong-apparatus, much smaller than, but similar 

 to, that used at the surface, acting, however, without clock work, by which 

 means a little gong is rung at the station, exactly as the gong rings above, 

 when the signals are made, so that the operator, having his signals repeated, 

 may know that it has been properly communicated to the engineer. The 

 ground wire at the station is made long enough to reach the neighboring 

 rock, where a hole is drilled a foot or two in depth, the wire inserted, and 

 packed with moist earth. 



There is a wire, with its connected boxes, for each compartment of the 

 shaft ; the signal gong for each compartment being placed directly in front 

 of its appropriate engine. The three wires in the shaft, however, are all 

 placed in the pump-compartment, being less liable to accident or derange- 

 ment there. The cost of this entire apparatus is stated at about fifteen hun- 

 dred doUars. It would appear to have some decided advantages for deep 

 mines or extensive works. Its unsatisfactory performance in this instance is 

 partly attributed to the uncertainty of the signals, some being caused by 

 other means than the hand of the operator, owing, perhaps, to the ease with 

 which the conducting wires may be accidentally brought into contact ; a dif- 

 ficulty for which, it would seem, a simple remedy might be found. An ob- 

 jection to the use of this method is the impossibility of sending a signal to 

 the engineer at the surface from points between stations. It is sometimes 

 desirable to stop a cage at intermediate points either for work to be 

 done there or on account of some accident. By the old arrangement the 

 1^ 



