374 
MINUTES OP PROCEEDINGS OP 
foot-tons, -which represents the work consumed by the resistance of 
the air in a range of 500 yards. 
Let now a Rodman spherical shot weighing 452 lbs. be supposed 
to be fired with an initial velocity of 1400 f.s. and strike an object 
500 yards from the gun. Referring to Tabled, we find 1396 f.s. 
= 1400—4 f.s. opposite 4100 feet in the distance column, and adding 
1500 feet, we obtain 5600 feet. Opposite 5600 feet in the distance 
column we find the velocity 1212 f.s. = 1216 —4, or the striking 
velocity would be 1216 f.s. As the energy has not been tabulated 
we must calculate it independently from the formula E — wv^-r-^SOg. 
We thus find the initial energy = 6143 and the striking energy = 
4604; giving a loss of energy in 500 yards = 6143 —4604= 1539 foot- 
tons, which work is consumed by the resistance of the air in a range 
of 500 yards. 
For experimental purposes suppose that it is required to fire a 
2501b. elongated shot from a 9-inch gun with such an initial velo¬ 
city that it may strike a target at a distance of 200 yards = 600 
feet, with the same velocity as if the shot had been fired with a 
charge of 43 lbs. from a distance of 1000 yards. Referring to Table 2, 
the initial velocity given to an elongated shot of 250 lbs. by a charge 
of 43 lbs, of powder is found to be 1314 f.s. When the shot has 
passed over 800 yards = 1000 — 200 yards, it has that velocity which 
ought to be the initial velocity of the shot fired from the experi¬ 
mental gun at a distance of 200 yards from the target. Referring to 
Table 9, we find a velocity 1315 f.s. = 13144 1 opposite 5600 feet in 
the distance column, to which we must add 800 yards = 2400 feet, 
making 8000 feet, opposite which we find 1186 f.s. = 1185 41. So 
that the velocity given by the distant gun 800 yards in advance of 
the gun, or 200 yards from the target, is 1185 f.s. The initial ve¬ 
locity to be given by the nearer or experimental gun is 1185 f.s. 
Referring to Table 2, we find that a charge of 29 lbs. gives an initial 
velocity of 1171 f.s. and that an addition of 1 lb. to the charge causes 
an increment of 16 f.s. in the initial velocity. It is plain, therefore, 
by proportional parts, that 14 oz. would give the required increment 
of 14 f.s. Thus the charge to be used by the experimental gun is 
29 lbs. 14 oz., which will give an initial velocity of 1171 4 14 = 1185 f.s. 
Again, turning to Table 9, opposite 8000 feet we find 1186 = 1185 
4l, and 200 yards or 600 feet further on, i.e. opposite 8600 feet, we 
find 1158 = 1157 41. Therefore 1157 f.s. is the striking velocity. 
In the same manner if we reckon from the distant gun fired with a 
charge of 43 lbs. we shall obtain a striking velocity at a distance of 
3000 feet = 1157 as before. 
Calculation and Use of the General Tables 20 & 21.—These tables have 
been most carefully calculated, the value of U having been changed 
for every change of 10 feet in the velocity. Since (Y-v)-~Yv = 2Us 
= (a number given in Table 1) xsx d 2 ~-w, if we suppose d 2 - r-iv = l we 
can calculate the values of (Y— v)-r-Yv for intervals of 10 feet in 
range. Afterwards, if we wished to know in what range any other 
similarly-shaped shot would lose a given velocity, we should have to 
