38e FEDERAL REFOBTEB. �purpose of more effectually confining the charge, so as there- by to heighten the efïect of the detonation ; third, by means of an additional charge of ordinary gunpowder, the explosion of the latter will cause the dynamite to go oS, even when it is only partially confined. Prom the aforesaid it will be un- derstood that a strong fulminating cap, if adapted to the fuse by being squeezed thereon, will cause dynamite to ex- plode under ail conditions of confinement or non-confine- ment, and that an additional charge of gunpowder or analo- gous substance will cause dynamite to explode only when confined, or partially confined, and that any ordinary mo'de of ignition, as used for gunpowder, for instance, a fuse, will determine the explosion of dynamite only under very close and resisting confinement. It is evident that the above described fulminating cap may be greatly varied in form, but the principle of its action lies in the sudden develop- ment of a very intense pressure or shock. In order to insure a perfect stability in the nitro-glycerine contained in the dynamite, the porous substance, before it is saturated with nitro-glycerine, is to be rendered alkaline by washing it with a solution of carbonate of soda, or lime-water, or analogous substance, in order to neutralize the acid and prevent any decomposition of nitro-glycerine from taking place. I would here remark, that the above described safety powder or dynamite, being nitro-glycerine absorbed in porous non- explosive substances, possesses many distinct properties from, and very practical advantages over, liquid nitro-glycer- ijie, and its explosion, except under very close and resisting confinement, requires a special ignition, as described above." Theclaim is: "The mode herein set forth of manufacturing the safety powder or dynamite herein described, and also the modes of firing the same by special ignition, as herein set forth." This English patent was the precursor of the patent No. 78,317. The story of Dittmar, as told by liim, is this : Before the end of 1865, at Bomlitz, near Walsrode, in Han- over, he experimented in mixing nitro-glycerine with nitro- cellulose, which was sawdust or wood fiber treated with nitrie acid or nitrie and sulphuric acids, and in mixing nitro-glycer- ��� �
