NITRO-GLYCERINE. 



363 



In vol. 21 of the Scientific American, the results of some experiments 

 in Switzerland by M. Von Arx, ai*e given as follows : 



He enclosed 2| cartridges in a bore 1.11 metres deep and three cen, 

 timetres diameter. This charge, when exploded, detached 6|^ cubic 

 metres of rock. In another experiment, 3^ cartridges, in a bore 1.32 

 metres deep, loosened 71 cubic metises of rock. M. Champion* has 

 published some experiments on the action of dynamite in breaking up 

 a mass of cast iron weighing 5000 kilos or about five tons. On one 

 side three holes were bored 25"^™ in diameter and 45 centimetres 

 deep. The central hole received a charge of about 150 grammes of 

 dynamite containing 75 % of nitro-glycerine in two cartridges. Its 

 explosion divided the block into two parts. The explosion of the 

 charges in the two other holes broke these up into many large 

 fragments, and these aga.in by smaller borings were reduced to small 

 pieces. In tamping charges of dynamite a wooden rammer is used, 

 and sand, damjD clay, or even water is employed as a tamping. 



Dynamite may be used for breaking vip boulders by simply laying 

 it on the top of the boulder, covering it with a little moist clay or 

 sand, and firing. In Sweden large boulders are broken up in this 

 manner, and at Rammelsberg in the Hartz Mountains it is used in 

 the same way for breaking up great masses of iron pyrites. 



Mr. Berkely, of Newcastle-upon-Tyne, in a paper " On the Practi- 

 cal employment of Dynamite,"! read before the Chemical Society of 

 that town, gives a most remarkable account of some experiments 

 with a large mass of cast iron, which he had tried in vain to break 

 with gunpowder, and the breaking up of which he easily effected 

 with dynamite. He placed 9 oz. of dynamite on a block of iron 

 2 feet 6 inches across and 18 inches thick, without any hole being 

 bored. The explosion cracked the block in two. The " stythe" 

 from nitro-glyceriiie is very suffocating, producing fearful headaches. 

 That from dynamite is said not to be so bad. 



Dynamite assumes a crystalline condition when exposed to cold, 

 in which it is not so active. The use of dynamite is attended with 

 a considerable saving over that of gunpowder. In the lead mines of 

 Goslar the saving is said by M. Hamel to amount to 17 % money 

 and half the time. In the iron mines at Zeerf, near Saarburg, to 25 % 

 money and half the time ; and at the Richlieu mine, near Freiberg , 

 to 30 ^ money and half the time. 



* Coroptes Rend., Ixxii, 770 ; Q. J. Chem. Soo., ix, 772. 

 4 t Chem. News xxix, 32. 



