An apparatus, devised by Horsley, was used, which consisted of an iron
stand with a ring support holding a hemispherical iron vessel, in
which paraffin or tin was put. Above this was another movable support,
from which a thermometer was suspended and so adjusted that its bulb
was immersed in molten material in the iron vessel. A thin copper
cartridge case, 5/8 in. in diameter and 1-5/16 in. long, was suspended
over the bath by means of a triangle, so that the end of the case was
1 in. below the surface of the liquid. On beginning the experiment the
material in the bath was heated to just above the melting point, the
thermometer was inserted in it, and a minute quantity of the explosive
was placed in the bottom of the cartridge case. The temperature marked
by the thermometer was noted as the _initial temperature_, the
cartridge case containing the explosive was inserted in the bath, and
the temperature quickly raised until the explosive flashed off or
exploded, when the temperature marked by the thermometer was again
noted as the _firing point_. The tables given show the results of
about six experiments with each explosive. The initial temperatures
range from 65° to 280° C. in some cases, but as the firing points
remained fairly constant, only the extremes of the latter are quoted
in the following table:
--------------------------------+-----------------------
Description of Explosive. | Firing Point in ° C.
--------------------------------+-----------------------
Compressed military gun-cotton. | 186 - 201
Air-dried military gun-cotton. | 179 - 186
" " " | 186 - 189
" " " | 137 - 139
" " " | 154 - 161
Gun-cotton dried at 65° C. | 136 - 141
Air-dried collodion gun-cotton. | 186 - 191
" " " | 197 - 199
" " " | 193 - 195
Air-dried gun-cotton. | 192 - 197
" " | 194 - 199
Hydro-nitrocellulose. | 201 - 213
Nitroglycerin. | 203 - 205
Kieselghur dynamite. No. 1. | 197 - 200
Explosive gelatin. | 203 - 209
Explosive gelatin, camphorated. | 174 - 182
Mercury fulminate. | 175 - 181
Gunpowder. | 278 - 287
Hill's picric powder. | 273 - 283
" " " | 273 - 290
Forcite, No. 1. | 184 - 200
Atlas powder, 75 per cent. | 175 - 185
Emmensite, No. 1. | 167 - 184
Emmensite, No. 2. | 165 - 177
Emmensite, No. 5. | 205 - 217
--------------------------------+-----------------------
_--C.E. Munroe, J. Amer. Chem. Soc._
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