~Ammonite, Bellite, Roburite, and Explosives of similar Composition.~--
These are required to stand the same heat test as compressed
nitro-cellulose, gun-cotton, &c.

~Chlorate Mixtures.~--The material must not be too sensitive, and must
show no tendency to increase in sensitiveness in keeping. It must contain
nothing liable to reduce the chlorate. Chlorides calculated as potassium
chloride must not exceed 0.25 per cent. The material must contain no free
acid, or substance liable to produce free acid. Explosives of this class
containing nitro-compounds will be subject to the heat test.

~Page's Regulator.~--The most convenient gas regulator to use in
connection with the heat-test apparatus is the one invented by Prof.
F.J.M. Page, B.Sc.[A] (Fig. 49). It is not affected by variations of the
barometric pressure, and is simple and easy to fit up. It consists of a
thermometer with an elongated glass bulb 5/8 inch diameter and 3 inches
long. The stem of the thermometer is 5 inches long and 1/8 inch to 3/16
inch internal diameter. One and a half inch from the top of the stem is
fused in at right angles a piece of glass tube, 1 inch long, of the same
diameter as the stem, so as to form a T. A piece of glass tube (A), about
7/16 inch external diameter and 1-1/2 inch long, is fitted at one end with
a short, sound cork (C, Fig. 50). Through the centre of this cork a hole
is bored, so that the stem of the thermometer just fits into it. The other
end of this glass tube is closed by a tightly fitting cork, preferably of
indiarubber (I), which is pierced by a fine bradawl through the centre.
Into the hole thus made is forced a piece of fine glass tube (B) 3 inches
long, and small enough to fit loosely inside the stem of the thermometer.

[Footnote A: _Chemical Soc. Jour._, 1876, i. 24.]