78 ANNUAL OF SCIENTIFIC DISCOVERY. 



NEW PROCESS FOR THE MANUFACTURE OF GUNPOWDER. 



At the recent Cornwall Midsummer Sessions, an application was made on 

 the part of Mr. Thomas Davey, one of the firm of Messrs. Bickford, Smith, 

 Davey, patent safety-fuse manufacturers, Tuckingmill, for a license to 

 erect a gunpowder mill and magazine at a place called West To wan, in the 

 parish of Illogan. Mr. Davey, on being asked what were the advantages of 

 the powder he proposed to manufacture, replied: "Perhaps I shall best do 

 this by reading to you the provisional specification : ' The improvements 

 in blasting-powder consist, first, in the employment of flour, bran, starch, 

 or other glutinous or starchy matter, to replace a part of the charcoal now 

 employed in the manufacture of powder ; second, in a new mode of graining 

 the same. By the substitution of the above-named, the component parts are 

 formed into a paste, and are easily combined and grained without danger of 

 explosion.' Gunpowder in present use is manufactured from certain propor- 

 tions of nitrate of potash, sulphur and charcoal, which, by the dangerous 

 process of trituration, are intimately combined ; the mixture is afterwards 

 pressed into cakes, dried, and then broken into grains of different sizes, ac- 

 cording to the use for which the powder is destined. In our process, instead 

 of grinding the powder, the nitrate of soda or potash is dissolved in sufficient 

 water to make a thick paste of the whole, and it is thus kneaded, to make it 

 homogeneous. It is then rolled into cakes, and cut into grains; or, while in 

 a paste, pressed through a perforated or wire sieve, with apertures or holes 

 of the size of the grain to be produced. The matter falls on endless canvas, 

 which is put slowly in motion, and passes on through a drying-room, bear- 

 ing with it a thin covering of the blasting composition divided in strings or 

 long grains by the sieve, and after being dried, it is passed between two roll- 

 ers, which break it into grains of a convenient size." 



Mr. J. J. Rogers : " Then you consider there is no danger of explosion, the 

 composition being wet?" Mr. Davey: "Not the slightest. AVe use 30 per 

 cent, of water." 



Mr. Rogers : " How do you prevent the coagulation of the wet particles 

 after they have fallen down from the sieve?" Mr. Davey : " By keeping the 

 canvas moving; but should there still be a slight connection between the 

 particles, it is broken on being passed through the wooden rollers, after the 

 composition is dried." 



Mr. Reynolds : " What difference is there in the appearance of your pow- 

 der and the powder manufactured by the old process ? " Mr. Davey : " Ours 

 is very like gunpowder-tea in appearance : it has no gloss." 



Messrs. Freeman & Sons, granite contractors, had tried the new powder, 

 and found that it possessed qualities superior to other blasting-powder, ac- 

 complishing all that was done by the latter at a saving of 37 per cent, in 

 weight. 



Captain N. Vivian, of Condurrow, said that he weighed the new powder 

 before testing, and found that the same quantity in bulk weighed 33 per cent, 

 less. He had six holes bored in very hard granite, and charged with powder, 

 putting no more into them than he should have done of the old powder, and 

 in every case it acted satisfactorily. It emitted much less smoke than the old 

 powder, which in blasting a mine was a matter of very great importance. 

 If it were sold at the same price in weight as the old powder, it would, of 

 course, be much cheaper, as it was much lighter. 



