upon Gun- powder, &c. 2 37 
made ufe of, it was found necefiary to load the barrel with an 
additional weight of more than 40 lbs. of iron. 
This additional weight of iron, which I (hall call the gun car- 
riage, as it was fo conftrucled as to ferve as a carriage to the 
barrel, is compofed of a bar of hammered iron 28 inches in 
length, 2,6 inches broad, and half an inch in thicknefs, which 
is bent in the middle of its length in fuch a manner, that its 
two flat fides or ends are parallel to each other, and diftant 
afunder two inches* In the middle of this bar where it is bent 
is a hole in the form of an oblong fquare, which, receiving the 
end of the breech-pin, fupports the lower end or breech of the 
barrel. The other end of the barrel is fupported and confined 
in the following manner. A ring or hoop of iron, near half 
an inch thick, and two inches in diameter, is placed in a ver^ 
tical position between the parallel fides of the bar, and near its 
two ends, and firmly fixed to them by fcrews. The barrel 
pafling through the middle of this ring is fupported upon the 
ends of three fcrews, which pafling through the ring in dif- 
ferent parts of its circumference all point towards its center. 
The carriage,- togpther with the barrel, was fufpended by the 
pendulous rods by means -of. two pair of polifhed trunnions that 
are fixed to the outfide of the carriage. They are placed in an 
horizontal line perpendicular to, and pafling through, the axis 
of the bore. 
Fig. 8. reprefents the barrel fixed to the carriage. 
b, c , is the bar of iron which forms the carriage feen 
edge-ways. 
2, 2, 4, 4, are the trunnions by which it was fufpended. 
d , e , is the barrel in its proper place. 
p y is the breech-pin*, which pafling through a hole in the 
middle of the bar, a, b , c , fupports the end, e , of the barrel ; and 
n , is the ring that fupports the end, d , of the barrel. 
Vol. LXXI. 2 K 
Fig. 
