44 
MINUTES OF PKOCEEDINGS OF 
In the figure, AB represents the line of the axis of the bore (making 
an angle of 18° with the horizontal), A being its intersection with the 
axis of the trunnions, and B with the axis of the bolt attaching the 
elevating-screw; C represents the axis of the axletree-arms at the 
shoulders, D that of the trannions at the elevating-screw box, E and F 
the bearings of the carriage upon the ground— i.e ., respectively of the 
wheels and trail. 
Let P = the maximum pressure exerted on discharge upon the car¬ 
riage, applied to it at A ,* and acting in the direction of 
the axis of the gun, 
P Y = the vertical component of P, 
F x = the horizontal component of P, 
B = the maximum vertical resistance of the axle and its bed, 
= 23*22 tons, 
W = the weight of the gun and carriage (without wheels), acting 
at their common centre of gravity Q, = 20 cwt., 
W' = the weight of the gun and carriage (with wheels), acting at 
their common centre of gravity P, = 24 cwt. 1 qr. 24 lbs. 
Then, AH , CE, Br } Qq y t being drawn perpendicular to the ground 
line, 
B x EF— P F x ZTP+ IF x qF- y 
~p Y _ B x EF — W x qF 
*’* “ llF 
_ 23*22 x 77*25 - 1*0 x 70*85 
~ 78*75 
= 21*87 tons, 
and P = 
pr 
sin 30° 
21*87 
*5 
= 43*74 tons; 
or, per square inch of area of cross section of the bore. 
43*74 
10*178 
4*297 tons. 
This being the maximum pressure transmitted to the carriage, if the 
maximum pressure exerted in the bore of the gun upon discharge be, 
as is said, 14 tons per square inch, there remains a balance between 
the two of 9*703 tons per square inch as the maximum force expended 
upon the metal of the gun. It may, however, be objected that 4-297 
* The absolute point of application is at first at a—the lowest point of the trunnion bearing— 
from which it is immediately changed along the bearing towards b. 
f These lines are respectively 43" , 25, 3l"‘0, SQ^'O, and 37"‘l in length. 
