| 187-200
Atlas powder (75% NG) | 175-185
Emmensite, No. 1 Sample had been stored in | 167-184
magazine for some months in |
a wooden box. |
" No. 2 Stored in tin case. | 165-177
" No. 5 " " | 205-217
__________________________________________________________|__________
| |
| deg.C. |
Powder used in Chassepot rifle | 191 | By Leygue & Champion.
French gunpowder | 295 | " "
Rifle powder (picrate) | 358 | " "
Cannon | 380 | " "
__________________________________|_________|________________________

Horsley's apparatus consists of an iron stand with a ring support, holding
a hemispherical iron vessel or bath in which solid paraffin is put. Above
this is another movable support, from which a thermometer is suspended,
and so adjusted that its bulb is immersed in the material contained in the
iron vessel. A thin copper cartridge-case, 5/8 inch in diameter and
1-15/16 inch long, is suspended over the bath by means of a triangle, so
that the end of the case is just 1 inch below the surface of the molten
material. On beginning the experiment of determining the firing point of
any explosive, the material in the bath is heated to just above the
melting point; the thermometer is inserted in it, and a minute quantity of
the explosive is placed in the bottom of the cartridge-case. The initial
temperature is noted, and then the cartridge-case containing the explosive
is inserted in the bath. The temperature is quickly raised until the
contents of the cartridge-case flash off or explode, when the temperature
is noted as the _firing point_.

[Illustration: FIG. 46.--HEAT TEST APPARATUS.]

Professor C.E. Munroe, of the U.S. Torpedo Station, has determined the
firing point of several explosives by means of this apparatus.

~The Government Heat Test (Explosives Act, 1875): Apparatus required.~--A
water bath, consisting of a spherical copper vessel _(a)_, Fig. 46, of
about 8 inches diameter, and with an aperture of about 5 inches; the bath
is filled with water to within a quarter of an inch of the edge. It has a
loose cover