Galvanic Battery in Blasting. 61 



right wire. This is my exploding cartridge : it cannot be easily 

 put out of order. The wires of the cartridge have only to be 

 made bright before they are fastened, by twisting them round 

 the positive and negative wires of the battery. 1 always place 

 the cartridge deep in the hole made to receive the powder, in 

 order that the pressure from the turnpeg may be taken off by 

 the quantity of powder above it. 



The wire I make use of is the common copper bell-wire. 

 The battery is the old Wedge wood trough, with 4-inch plates, 

 double coppers. 1 prevent the zinc plates from touching the 

 copper by small pegs of wood passed through the four cor- 

 ners. Wooden troughs with moveable divisions were tried, 

 but not with any good result. A wooden trough with the 

 plates in a frame of wood with varnished paper between the 

 copper was tried, but the porcelain trough far surpassed them. 

 My first experiment was blasting single blocks ; the effect was 

 much better than when the fuze was used, in consequence of 

 the clay being more firmly driven round the wires than it would 

 be round the larger surface of the fuze. 2ndly, I selected 

 two large blocks nearly in line ; the first block was 43 feet 

 from the battery; the second block 113 feet from the battery, 

 and the blocks consequently were 70 feet from each other. On 

 dipping the plates the explosions took place in quick succession; 

 the battery consisted of 30 pairs of 4-inch plates. 3rdly, I 

 wished to try the effect of a simultaneous explosion of two blasts 

 on a very large block firmly tied together by rivets. The po- 

 sitive wires of each cartridge were fastened to the positive 

 connecting wire, and in like manner the negative wire. The 

 effects of this simultaneous explosion were very good ; the 

 exciting liquor being weak, the connecting wires were short- 

 ened to 98 feet. 4th, To amuse some friends, I exploded 

 some powder in one of the ponds, depth 10 feet; length of 

 wire 210 feet; 40 pairs of plates, with old exciting liquor : — 

 the experiment succeeded to the delight of all ; a large eel 

 was killed by the blow-up. 1 have no doubt but that wild- 

 fowl will yet be killed by means of shells placed at low water 

 on the banks where they feed; and by means of long connect- 

 ing wires, the shells can be made to explode simultaneously 

 among the birds. 



I find that 10 pairs of 4-inch plates free from oxide and 

 charged with the following exciting liquor — water, 6^ quarts ; 

 sulphuric acid of commerce, 4^ ounces; nitrous acid,45 ounces; 

 will ignite powder with a wire 101 feet long. 20 pairs of plates 

 ignited powder at the distance of 353 feet. I tried to repeat 

 this experiment, but did not succeed, though the plates were 



