34 Use of the Galvanic Battery m Blasting. 



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 smface 

 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. 3rdiy, I wished to try the effect of a simultaneous 

 explosion of two blasts on a very large block firmly tied together 

 by rivets. The positive 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 

 shortened 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 ex- 

 periment succeeded to the delight of all ; a large eel was killed 

 by the blow-up. I have no doubt but 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 connecting wires, the shells can be 

 made to explode simultaneously among the birds. 



1 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, 4^ ounces ; will ignite 

 powder with a wire 101 feet long. 20 pairs of plates ignited pow- 

 der at the distance of 353 feet. I tried to repeat this experiment, 

 but did not succeed, though the plates were only three times im- 

 mersed in the acid, and only for about two seconds each time. I 

 tried the same battery at 268 feet, and did not succeed. The 

 plates were then well washed, and fresh exciting liquor made : 

 the ex}ieriment again failed ; the plates were quite inactive. The 

 next day I tried the same plates and the same exciting liquor, and 

 succeeded at 268 feet. From this it seems impossible to say 

 how many pairs of plates would be required to produce uniform 

 effects at long distances. I suspect that the zinc plates do not act 

 equally in producing the electricity, which causes this variation. 



I should have liked very much to have tried the conducting 

 properties of different sized wires, but had not an opportunity of 

 getting them here. 



