106 ANNUAL OF SCIENTIFIC DISCOVERY. 



Coal. Tn the ironstone mines of Morawieza the experiment was 

 made in less firm rock, with large bores, and a charge of 25 to 30 

 pounds of haloxylin produced an effect exceeding by one-third that 

 of gunpowder. Such evidence as this is sufficient to prove that 

 the non-explosive has, at least, some advantage over ordinary 

 blasting powder; and when the quantity of blasting powder an- 

 nually used in Great Britain is taken into consideration, it will be 

 readily understood that, assuming even the smaller estimate 30 

 per cent, of saving, the inducement for the miners of this country 

 to adopt it will be ample to insure, under any circumstances, a 

 fair remuneration to those undertaking the manufacture. Lon- 

 don Mining Journal. 



DIAZOBENZOLE. 



This salt, discovered by Mr. Peter Griess, and named by him 

 nitrate of diazobenzole, is prepared by passing nitrous acid 

 through a solution of aniline in four times its volume of alcohol. 

 The gas is passed through this solution until the addition of ether 

 to a small portion causes the copious precipitation of white acicular 

 crystals. When this point is reached, the whole of the reddish- 

 brown liquor is mixed with ether ; the crystals are then allowed 

 to subside, and separated as far as possible from the mother liquor. 

 They are then taken up with cold dilute alcohol, and re-precipi- 

 tated by the addition of ether, when they are obtained as long 

 white needles. They must be treated with the greatest care, and 

 dried in the air, or over sulphuric acid ; heated even below 100 

 Cent, they explode with great violence, far surpassing that of ful- 

 minating silver; friction, pressure, and concussion also cause ex- 

 plosion, with extreme destructive action. According to the 

 French patent the compound is produced in the following way : 

 1 equivalent of hydrochlorate of aniline is mixed with 2 equiva- 

 lents of hydrochloric acid, and to this mixture is added very 

 gradually 1 equivalent of nitrate of soda in strong solution. This 

 mixture is left to itself so long as any nitrogen is disengaged. 

 AVhen the evolution of nitrogen has ceased, it only remains to ex- 

 tract the diazobenzole, and get it in a state fit for commerce and 

 use. To this end a concentrated solution of 1 equivalent of bichro- 

 mate of potash in 1 equivalent of hydrochloric acid is added, 

 which causes a precipitate of chromate or chlorochroniate of dia- 

 zobenzole. 



NEUMEYER'S POWDER. 



M. Neumeyer, of Saxony, has invented a powder composed of 

 the same constituents as ordinary gunpowder, though in different 

 proportions, which in contact with the air will burn but not ex- 

 plode, but when confined in a cannon or a mine will explode with 

 great force. It is much less dangerous than ordinary blasting 

 powder, and produces greater effects with the same amount of 

 material. It requires an intense heat for explosion, about 400 C. 

 or 752 F. The advantages of this powder seem to be that its 

 safety from explosion as long as it is in contact with the atmos- 



