284 Count Rumford's Experiments to determine 
velocities, they were often seen to pass through the air on fire ; 
and when this was the case no vestige was to be found. 
They sometimes passed, on fire, through several of the fore- 
most screens without setting them on fire, and set fire to one 
or more of the hindmost, and then went on and impinged 
against the board, which was placed at the distance of 12 inches 
behind the last screen. 
It is hardly necessary for me to observe, that all these expe- 
riments prove that the combustion of gunpowder is very far 
from being so instantaneous as has generally been imagined. 
I will just mention one experiment more, in which this was 
shown in a manner still more striking, and not less conclusive. 
A small piece of red-hot iron being dropped down into the 
chamber of a common horse pistol, and the pistol being ele- 
vated to an angle of about 45 degrees, upon dropping down 
into its barrel one of the small globes of powder (of the size of 
a pea), it took fire, and was projected into the atmosphere by 
the elastic fluid generated in its own combustion, leaving a 
very beautiful train of light behind it, and disappearing all at 
once, like a falling star. 
This amusing experiment was repeated very often, and with 
globes of different sizes. When very small ones were used 
singly, they were commonly consumed entirely before they 
came out of the barrel of the pistol ; but when several of them 
were used together, some, if not all of them were commonly 
projected into the atmosphere on fire. 
I shall conclude this paper by some observations on the prac- 
tical uses and improvements that may probably be derived from 
these discoveries, respecting the great expansive force of the 
fluid generated in the combustion of gunpowder. 
