278 Count Rumford’s Experiments to determine 
be only equal to the pressure of 1000 atmospheres. It appears, 
however, from the result of these experiments, that even ad- 
mitting the elasticities to be as the densities, as Mr. Robins 
supposes them to be, the initial force of this generated elastic 
fluid must be at least twenty times greater than Mr. Robins 
determined it; for T 4 ^ 8 ^, the density of the elastic fluid in the 
experiments in question, is to 1, its density when the powder 
quite fills the space in which it is confined, as 9431 atmo- 
spheres, the measure of its elastic force in the experiments in 
question, to 20108 atmospheres ; which, according to Mr. Ro- 
bins’s theory respecting the ratio of the elasticities to the den- 
sities, would be the measure of its initial force. 
But all my experiments tend uniformly to prove, that the 
elasticities increase faster than in the simple ratio of the corre- 
sponding densities ; consequently the initial force of the gene- 
rated elastic fluid must necessarily be greater than the pressure 
of 20108 atmospheres. 
In one of my experiments which I have often had occasion 
to mention, the force actually exerted by the fluid must have 
been at least equal to the pressure of 34752 atmospheres. The 
other experiments ought, no doubt, to show, at least, that it is 
possible that such an enormous force may have been exerted 
by the charge made use of ; and this, I think, they actually 
indicate. 
In the first set of experiments, which were made when the 
weather was cold, though the results of them uniformly show- 
ed the force of the powder to be much less than it appeared to 
be in all the subsequent experiments, made with greater 
charges, and in warm weather, yet they all show that the ratio 
