ATLANTIC GIANT POWDBB 00. V. DITTMAB POWDBB 00. 339 �sorial earth having, by experiment, proved itself so much inferior to combinations with combustible and explosive sub- stances, as absorbents, I, in my applications for such letters patent, wholly discarded inert substances, such as said infu- sorial earth, chalk, brick-dust and the like, and made such applications for combinations with combustible and explosive substances only. It was upon the return of my application to the British government that I was first informed of the fact that Nobel, during bis sojourn in England, had applied for and obtained English letters for my invention aforesaid. The resuit of my application for an English patçnt was a provisional protection. » * * * The Prussian govern- ment refused to grant me letters patent, upon the application made by me as aforesaid, upon the ground that the mixture of nitro-glycerine and powder had been empioyed for blasting purposes." Dittmar allowed his Eussian application to fall, and did not perfect a patent in England for what was covered in England by such provisional protection. �The English provisional protection consisted of a provis- ional specification, filed by one Johnson, December 5, 1867, on a communication from Dittmar. It was as foUows: "Hitherto the employment of nitro-glycerine for blasting and similar purposes bas been attended with considerable danger, and the object of this invention is not only to render its employment safe, but to enable it to be transported and stored free from its present attendant liability to explosion. In carrying out this invention the nitro-glycerine is mixed with a porous combustible substance, such, for example, as finely divided wood charcoal, which, by preference, bas been previously saturated with a solution of saltpetre, or nitrate of soda, or mixtures of the same, and also with a solution of carbonate of soda, and subsequently dried, so as to expel the water empioyed for effecting such solution; or the nitro- glycerine may be mixed with what is knowa as nitro-cellulose, that is to say, with finely divided wood or other solid ligneous matter, which bas been treated with nitric and sulphuric acid in a manner similar to that empioyed for the production of gun cotton; or the nitro-glycerine may be mixed with saw- ��� �
