114 ANNUAL OF SCIENTIFIC DISCOVERY. 



powder is placed in the cylinder; the hammer, falling, forces its 

 plunger into the cylinder, compressing and iieating the air, which 

 explodes the powder, forcing the hammer up again, and forcing 

 the cylinder downward, witii an effect fully 8 times as great as 

 from the falling of the weight alone. At tiie top of the guide- 

 frame is suspended a plunger, which fits into a cylinder in the 

 top of the hammer, thus making an air-chamber to receive the 

 blow of the hammer, in case of an over-charge of powder, that 

 no danger may result to the machine. Tlie model which was ex- 

 hibited on this occasion had a ram of about 3 pounds' weight, and 

 a fall of 8 feet. The charge employed was half a grain of white 

 gunpowder, made of chlorate of potash, ferrocyanide of potassi- 

 um, and sugar. With a larger instrument, whose ram weighed 

 73 pounds, with a fall of 20 feet, the charge was 14 grains of the 

 same powder. A pile placed under this, and driven one quarter 

 inch at a stroke by the fall of tiie ram, without the use of powder, 

 was driven two inches at each stroke when the powder was used, 

 and after being driven, with a square end, into hard ground, to a 

 depth of 4 feet, showed no splitting or injury to its head." — 

 Journal of the Franklin Institute. 



AMMONIA POWDER. 



The following account of a new explosive material appears iu 

 the "Kolnische Zeitung," May 19, which gives tiie "iMilitor- 

 Wochen-blatt " as its authority: ** It is now some time since the 

 proprietors of the Nora-Gyttorn Powder Mills obtained a patent in 

 Sweden for tlie discovery of the so-called * ammonia powder,' a 

 substance which has hitherto been only emplo3'ed in a few mining- 

 districts, but which otherwise seems wholly unknown. We are, 

 therefore, fully justified in calling attention to the particular prop- 

 erties of this new explosive material. During the short time tiiat 

 it has been employed, it has won the approval, not only of the 

 proprietors of mines, but also of the working miners themselves. 

 Its explosive force may be compared to that of nitro-glycerine, . 

 and, C()nse(]uently, far surpasses that of dynamite. It cannot be 

 exploded by a flame or by sparks, and the explosion is effected 

 by a heavy blow from a hammer. Blast-holes loaded with tiiis 

 l)owder are exj)loded b}' means of a })()werful cap, or, better, by 

 means of a cartridge containing common powder, for this forms. 

 a more reliable exploder. IMiners who have beenobh'ged to give 

 up the use of nitro-glycerine, on account of the danger connected 

 witii this powerful explosive agent, have a most satisfactory sub- 

 stitute in the ammonia powder, as the danger of using it is so 

 snjall that it surpasses in safety every other blasting material. 

 One of the useful and important properties of this new powder 

 is, that it does not require heating in cold weather, whilst nitro- 

 glycerine and dynamite must first of all be warmed, and this has 

 been the cause of many accidents. The price of ammonia pow- 

 der is the same as that of dynamite." The same paper further 

 adds: "According to information we have received, ammonia 



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