The Chemistry of Powder and Explosives - Sciencemadness Dot Org

210 NITRIC ESTERS
and 7500 meters per second. Naoum 22 reports that blasting
gelatin (92-93% NG, 7-8% collodion nitrocotton) has a low
velocity of 1600-2000 meters per second and a high velocity of
about 8000. Blasting gelatin filled with air bubbles always shows
the higher velocity, while clear and transparent blasting gelatin
almost always shows the lower velocity of detonation. Frozen
dynamite is more difficult to initiate, but always detonates at the
high velocity. 28
Certain properties of nitroglycerin and of other explosives,
reported by Brunswig, 24 are tabulated below and compared in a
manner to show the relative power of the substances. The spe-
Nitroglycerin
Nitromannite
Blasting gelatin
(93% NG, 7% NO
75% Guhr dynamite
Nitrocotton (13% N)
Picric acid
Black powder
Ammonium nitrate
Mercury fulminate
SPECIFIC
VOLUME,
LITERS
712
723
710
628
859
877
285
937
314
EXPLO-
SION
TEMPER-
ATURE, °C.
3470
3430
3540
3160
2710
2430
2770
2120
3530
HEAT OF
EXPLO-
SION,
CALORIES
1580
1520
1640
1290
1100
810
685
630
410
CHARAC-
TERISTIC
PRODUCT
1,125,000
1,099,000
1,164,000
810,000
945,000
710,000
195,000
590,000
129,000
cific volume is the volume, at 0° and 760 mm., of the gaseous
products of the explosion. This number multiplied by the heat
of explosion gives the characteristic product which Berthelot
considered to be a measure of the mechanical work performed
by the explosion. The mechanical work has also been estimated,
differently, in kilogram-meters by multiplying the heat of explosion
by 425, the mechanical equivalent of heat.
Naoum 25 reports the results of his own experiments with nitroglycerin
and with other explosives in the Trauzl lead block test
(sand tamping), 10-gram samples, as shown below. The Trauzl test
is essentially a measure of brisance, but for explosives of similar
22 Op. tit, p. 145.
23 Herlin, Z. ges Schiess- u. Sprengstoffw, 9, 401 (1914).
24 Brunswig, "Explosivstoffe," 1909, cited by Naoum, op cit, p. 152.
2 *>Op. at., p. 156.