THE COMSTOCK IVH^ES. 143 



wire, involving not only considerable expense of money and labor in replac- 

 ing the same, but, what is more important, a great detention of the under- 

 ground work, since, whenever such an accident occurs, all work of extraction 

 must be suspended at such stations or levels where signal communication has 

 been interrupted, and a number of men must consequently remain idle until 

 repairs are completed. An improvement has lately been made, in some of 

 the mines, by the substitution of half-inch ratlin rope, in place of the wire, 

 which, for strength and durability, gives much greater satisfaction. The rope 

 or wire is kept in place, near the side of the shaft, by iron staples, through 

 which it moves freely. 



To avoid the inconveniences just referred to, arising from the frequent 

 breaking of the bell wire, a method of signalizing by electric telegraphy, not 

 common in mines, was introduced by the Savage company in the spring of 

 1868. It gave great satisfaction for a time, but was afterward given up, 

 owing to reasons not very definitely explained to the writer. It would ap- 

 pear, however, that its defects might be remedied, and the application of tel- 

 egraphy to this purpose rendered useftil. 



The apparatus, as introduced at the Savage, consists of a battery, placed 

 in the engine-room, with which two wires are connected, one leading to the 

 ground, the other to a coil, fixed in a box near the engine driver, on the 

 magnetic condition of which coil the striking of the gong depends. From 

 this same coil another wire leads down the shaft to the station to be commu- 

 nicated with, where the end is received in a box, which also contains the 

 end of another wire leading into the ground at the station. The earth is 

 therefore used for completing the circuit. When the ends of the two wires, 

 in the box at the station in the shaft, are disconnected, the circuit is broken ; 

 but, if they be brought together, it is complete, and the current, passing 

 through the coil in the box in the engine-room, renders it magnetic, in which 

 condition it acts upon an iron bar, so placed beneath it as to be lifted by at- 

 traction when the coil is magnetic, or to fall by its own weight when the coil 

 is deprived of its magnetic force. By the movement of this bar the gong is 

 struck and caused to ring. The battery employed in this arrangement is of 

 the kind known as HiU's. It consists, in this instance, of thirty-two glass 

 jars or cells, four inches in diameter and in depth, each cell furnished with a 



