234 
CAPTAIN NOBLE AND MR. F. A. ABEL ON FIRED GUNPOWDER. 
The value of p Q , that is, the pressure corresponding to a gravimetric density of unity, 
is taken at 6554 atmospheres =43 tons per square inch, this value being the result of 
our further experiments corrected for perfectly dry powder. 
Table IX.—Showing the value of the constants in equation (30). 
p 0 =43 tons per square inch = 6554 atmospheres, 
a = -57 
0 = 
1-2957 
c,= 
•2324 
c.= 
•1762 
X = 
•45 
From equation (30), with the values of the constants given in Table IX., we have 
calculated the tensions for various gravimetric densities ranging from 1 to '05, and have 
expressed these tensions in kilogrammes per square centimetre, in tons per square inch, 
and in atmospheres. 
We have placed in the same table, for purposes of comparison, the pressures which 
would rule were the gases permitted to expand without production of work in a 
vessel impervious to heat, or, what amounts to the same thing, the pressures that 
would have place were the charges exploded in a perfectly closed cylinder with the 
corresponding gravimetric densities* 
