254 Count Rumford’s Experiments to determine 
metal was 1^ inch; or, it was 5 times as thick as the dia- 
meter of its bore. The charge of powder was extremely small, 
amounting to but little more than ■— of a cubic inch : not so 
much as would be required to load a small pocket pistol, and 
not one-tenth part of the quantity frequently made use of for 
the charge of a common musket. I should be afraid to relate 
the result of this experiment, had I not the most indisputable 
evidence to produce in support of the facts. This inconsider- 
able quantity of gunpowder, when it was set on fire by the 
application of the red-hot ball to the vent tube, exploded with 
such inconceivable force as to burst the barrel asunder in which 
it was confined, notwithstanding its enormous strength : and 
with such a loud report as to alarm the whole neighbourhood. 
It is impossible to describe the surprise of those who were spec 
tators of this phaenomenon. They literally turned pale with 
affright and astonishment, and it was some time before they 
could recover themselves. The barrel was not only completely 
burst asunder, but the two halves of it were thrown upon the 
ground in different directions : one of them fell close by my 
feet, as I was standing near the machinery to observe more 
accurately the result of the experiment. Though I thought it 
possible that the weight might be raised, and that the gene- 
rated elastic vapour would make its escape, yet the bursting of 
the barrel was totally unexpected by me. It was a new lesson 
to teach me caution in these dangerous pursuits. 
It affords me peculiar satisfaction in laying these accounts 
before the Royal Society, to be able to produce the most re- 
spectable testimony of their authenticity. 
My friend Sir Charles Blagden, one of the worthy Secre- 
taries of the Society, visited Munich in the summer of the year 
