equired. The lid contains
several small holes, into each of which is soldered a thick copper tube
about 5 mm. in diameter, and 3 inches long, with a rather larger one in
the centre in which to place a thermometer. The dish is filled with Rose's
metal, or paraffin, according to the probable temperature required. The
firing point is then taken thus:--After putting a little piece of asbestos
felt at the bottom of the centre tube, the thermometer is inserted, and a
small quantity of the explosive to be tested is placed in the other holes;
the lid is then placed on the dish containing the melted paraffin or
metal, in such a way that the copper tubes dip below the surface of the
liquid; the temperature of the bath is now raised until the explosive
fires, and the temperature noted. The initial temperature should also be
noted.

THE FIRING POINT OF VARIOUS EXPLOSIVES (by C. E. Munroe).
(Horsley's Apparatus used.)

_____________________________________________________________________
|
| deg.C.
Nitro-glycerine, 5 years old (a single drop taken) | 203-205
Gun-cotton (compressed military cotton, sp. gr. 1.5) | 192-201
Air-dried gun-cotton, stored for 4 years | 179-187
Ditto, stored for 1 year | 187-189
Air-dried collodion-cotton, long staple "Red Island |
cotton," 3 years old | 186-191
Air-dried collodion, 3 years old, stored wet | 197-199
Hydro-nitro-cellulose | 201-213
Kieselguhr dynamite, No. 1 | 197-200
Explosive gelatine | 203-209
Mercury fulminate | 175-181
Gunpowder (shell) | 278-287
Hill's picric powder (shells) Been in store 10 years. | 273-283
Ditto (musket) Composed of-- | 282-290
Ammonium picrate 42.18 % |
Potassium picrate 53.79 " |
Charcoal (alder) 3.85 " |
________ |
|
99.82 |
Forcite, No. 1