to heat, and even when quite pure will not stand a temperature of 100° C.
for a longer period than a few hours, without undergoing decomposition. Up
to a temperature of 45° C., however, properly made and purified nitro-
glycerine will remain unchanged almost indefinitely. The percentage
composition of nitroglycerine is as follows:--

Found. Theory for C_{3}H_{5}(N0_{2})_{3}.

Carbon 15.62 15.86 per cent.
Hydrogen 2.40 2.20 "
Nitrogen 17.90 18.50 "
Oxygen ... 63.44 "

The above analysis is by Beckerheim. Sauer and Adou give the nitrogen as
18.35 to 10.54 per cent. by Dumas' method; but I have never found any
difficulty in obtaining percentages as high as 18.46 by the use of Lunge's
nitrometer. The decomposition products by explosion are shown by the
following equation--

2C_{3}H_{5}(NO_{3})_{3} = 6CO_{2} + 5H_{2}O + 6N + O;

that is, it contains an excess of 3.52 per cent. of oxygen above that
required for complete combustion; 100 grms. would be converted into--

Carbonic Acid (CO_{2}) 58.15 per cent.
Water 19.83 "
Oxygen 3.52 per cent.
Nitrogen 18.50 "

The volume of gases produced at 0° and 760 mm., calculated from the above,