138 



When a rock is to be rent by this new system of operation, 

 a hole is first bored, of the requisite depth and diameter, 

 then cleared and dried in the usual manner. One>half of 

 the requisite charge of powder is now to be poured in, and 

 on this is placed the galvanic cartridge, whose wires reach to 

 the surface of the rock ; then pour upon the cartridge the 

 remainder of the powder ; let a wad of straw or oakum be 

 pressed into the hole until it is at a point about two feet from 

 the powder, then upon this wad pour in dry sand ; attach the 

 cartridge wires to the main conducting wires ; let all the men 

 retire to a place of safety, carrying with them the battery 

 cord, which may be of any required length ; pull this cord ; 

 the battery is thrown into action ; the electricity runs through 

 the fine wire, fuses it, ignites the charge, and the rock is 

 rent. Such is the simple process, which requires far less 

 time than the old method, and is one of perfect safety during 

 the whole of the operation. In the sinking of shafts, the 

 use of galvanism will be found most valuable, as the work- 

 man can be drawn up in perfect safety, whereas, when the 

 fuse is used, he has to remain suspended several minutes 

 above the burning train, and the whole may explode before he 

 gains the surface, causing certain death. Such an accident 

 has frequently happened, to my own knowledge, and I have 

 too often heard of its occurrence. 



I need not take the trouble to point out the many cases 

 in which this process may be the means of saving human 

 life ; for those conversant with mining and quarrying 

 operations must now be well aware of its great value, 

 and in subaqueous explosions galvanism is indispensable. 

 I have expended much time and money in bringing it to 

 its present perfection, but I shall consider myself amply 

 repaid if it be the means of saving one fellow creature 

 from injury. 



