Page:Federal Reporter, 1st Series, Volume 1.djvu/341

ATLANTIC GIANT POWDEB 00. V. DITTMAR POWDEB 00. 333 �and resisting confinement, when a violent explosion ensues. Against shocks or blows the above mixture is far less sensi- tive than nitro-glycerine alone. Owing to the aforesaid properties of the mixture described, its use for blasting meta! or very sound rock requires no other firing than an ordinary safety fuse. In shattered rock or coal, on the other hand, it will cause no real explosion at ail, the gas will leak out through the crevices and prevent a great accumulation of pressure from the explosive medium, which alone can determine the detonation of nitro-glycerine when absorbed in porous sub- stances, such as, for instance, charcoal or silica. For this reason a special igniter is used to explode the above mixture in fissured or shaky rocks, or wherever it is to be used without close confinement. That special igniter consists of a kind of percussion-cap, wherein the fulminate is caused to develop a very high gaseous pressure before it bursts, which may be attained either by increasing the charge of fulminate or diminishing the leakage of gas before the cap bursts. This cap is adapted to the end of a safety fuse, whereby it is ignited." �The full specification of this patent was filed on the sixth of November, 1867. It read thus : "This invention relates to the use of nitro-glycerine in an altered condition, which renders it far more practical and safe for use. The altered condition of the nitro-glycerine is effected by causing it tb bë absorbed in porous inexplosive substances, such as charcoaîl, silica, paper, or similar materials, whereby it is converted into à powder, which I call dynamite, or Nobel's safety powder. By this absorption of the nitro-glycerine in some porous substance, it acquires the property of being in a high degree insensible to shocks, and it can also be burned over fire without exploding, The aforesaid safety powder or djma- inite is exploded first, when under very close and resisting confinement, by means of a spark, or any mode of ignition used for firing ordinary gunpowder; second, without or dur- ing confinement, by means of a special fulminating cap, con- taining a strong charge of fulminate, which is adapted to the end of a fuse, and is strongly squeezed to the latter, for the ��� �