414 
MINUTES OF PROCEEDINGS' OF 
Gay-Lussac obtained 450 volumes of gas, and, estimating the temperature 
at 1000° C., deduced a pressure of 2137 atmospheres (14*3 tons). 
Piobert accepted Gay-Lussac's determination of the quantity of gas pro¬ 
duced, but estimated the temperature at 2400° C., and thus deduced a 
pressure of between 4000 and 5000 atmospheres for the permanent gases 
alone. Counting the other products, which at this temperature he con¬ 
sidered would be in a state of vapour at a high tension, he estimated the 
total pressure at 9600 atmospheres (64 tons). 
With regard to the solid products, he says :—* 
“There thus exist two very distinct periods during the continuance of the 
phenomenon of explosion; the first during which the products are in the state of 
elastic fluids, the tension of the vapours adding themselves to those of the per¬ 
manent gases; and the second period during which the permanent gases alone 
act, the vapours being condensed, and forming those residues of combustion termed 
1 crasse,’ and which deposit themselves on the sides of the chamber in which the 
powder is shut up, because these products have not been able to escape during the 
time they were in the gaseous state. 
“The explosion of powder may thus present great anomalies in the effects 
produced from one point of action to another, when the elastic fluids act only 
during the first period, which is that of greatest effort, and this should be taken 
into consideration every time the circumstances of firing do not remain identically 
the same; also the force of powder measured during this period has given rise to 
a great many valuations very different from one another. When, on the contrary, 
the force of the powder is measured after these effects, during the second period, 
it is estimated at much less than it is in reality, because in this case no account is 
taken of the tension of the vapours which no longer exist.” 
Bunsen and Schischkoff obtained 193*1 volumes of gas, the production 
of which was attended by the development of 619'5 units of heat, and from 
this, taken in conjunction with the known capacities for heat of the products, 
they concluded that the temperature of the flame of powder, exploded in a 
closed space so that the gases cannot freely expand, is 3340° G. With 
regard to the residue, they say :—f 
“ Although a slight volatilisation cannot be denied, it may be shown from the 
calculation of the temperature of the flame that the tension caused thereby cannot 
amount to one atmosphere. The temperature of the flame of hydrogen burning in 
air is 3259° C. A fragment of powder residue fused on a thin platinum wire 
was gradually volatilised in a jet of hydrogen burning in air, but it never reached 
ebullition, and hence the tension of its vapour could never have attained one atmo¬ 
sphere.” 
They conclude that the pressure can never reach 4500 atmospheres 
(30 tons). 
Mr. AbelJ remarks :—■ 
“ The conclusions to which Bunsen and Schischkoff have been led by their 
elaborate investigation of the products of decomposition of gunpowder are, in the 
* “ Traite d’Artillerie theorique et pratique.” 
f “ Occasional Papers, R.A. Institution,” p. 310; 
J Chemist to the War Department. 
