53 
same as that shown by the experiments of Canton. Some 
time after Professor Oersted made similar experiments by- 
employing a stout glass vessel and using a column of mercury 
to give the pressure, having the like inside cylinder as that 
of Perkins to mark the result, which confirmed the same rate 
as that shown by Perkins and Canton. 
Appendix II. 
On Perkins ’ Steam Gun. 
Mr. Perkins conceived the idea of employing steam at a 
very high pressure for discharging projectiles with greater 
rapidity and effect than could be done by the common use of 
gunpowder. To effect this object he devised a plan for 
heating water more intensely than could be done by any 
boilers then known, viz. — that of employing a great number 
of iron or copper tubes, with their ends fastened into plates, 
with chambers or cavities for receiving the water at one end 
and emitting the steam at the other. 
This apparatus was placed in the midst of a furnace for the 
heat to act directly on the water in the tubes, and thus, as 
Mr. Perkins phrased it, the water could be madejed hot and 
flash into steam with a force exceeding that of gunpowder. 
Then a gun barrel, with its breech opposite the valve opening 
from the steam chamber, and an apparatus for conducting the 
balls into the space between the breech of the barrel and the 
outlet of the steam, and, the valve opening at the same time, 
the steam issued and propelled the balls through the gun in 
rapid succession with a force about equal to common powder, 
which could be continued as long as the heat of the furnace 
could keep up the pressure. He found that from fifty to a 
hundred balls per minute were shot forth to a target, about 
one hundred yards, with a force nearly equal to that of a 
common musket, and of course by having ten such guns fixed 
to the same furnace, from 500 to 1,000 balls might be dis- 
charged per minute. His experiments were witnessed by the 
