26 O. N. Rood on Elongated Projectiles. 
Single Cones. (Weight 105-01 grains.) 
Rifle No. 2. Initial Velocity 1917 ft. 
Distance. Time of Flight. Average Velocity. 
220 yards, "4175 1580 feet 
500 * 1:3080 1146 “* 
Double Cones. (Weight 100°8 grains.) 
Rifle No. 2. Initial Velocity 1867 ft.. 
Time of Flight. A 
Distance. verage Velocity. 
220 yards, “4552 1449 feet. 
500 * 1°4120 1062 “* 
It will be seen from these tables that the flight of the double 
is slower than that of the single cone, particularly at high veloci- 
ties: this disproportion diminishes as we use lower velocities, 
ut even here the new seems to possess no advantage over 
the old form—the sharpness of the stern not at all compensating 
for the necessary bluntness of the bows. It occured to me that 
this inferiority in the flight of the new balls might be owing to 
a disfiguration in their shape produced by the explosion of the 
owder: a number of them were accordingly fired into a bank of 
snow distant 500 yards: when dug out they were found to be 
as perfect in their proportions as at the time of loading, 
It would seem that if the conical has any advantage over the 
flat base, it is only at velocities as low as 400 or 500 feet per 
second. These experiments also tend to show that the vacuum 
behind a projectile does not suddenly cease at a velocity of 
1150 feet, but that its diminution is very gradual: they farther 
indicate to some extent the importance of making the forward 
part of the ball sharp when a high velocity is desired. Indeed, 
the air struck by the forward part of the ball seems to be thrown 
from it with such force, at high velocities, that a vacuum is pro- 
du ehind it, whatever its form may be; and the vacuum is 
more complete the blunter the point is made. This may account 
fully for the disadvantage of the double cone. 
It is well understood that the weight of the projectile exercises 
much influence on the time of its flight at the longer ranges: the 
time of flight of a ball weighing 105-01 grains and starting with 
a velocity 1917 feet has already been given: below are the re- 
ier ball. be 
sults obtained with a heavier b 
Rifle No.1. Weight of Ball 248°6 grains. 
Initial Velocity 1602 ft.* 
Although the difference in the initial velocities was 315 feet, 
yet at 220 yards the difference in the average velocities was 
* The initial velocity was calculated from determinations made with rifles Nos. 2 
and 3. The determination from No. 2 when reduced gave it 1582°5 ft., that from No. 8, 
1621 ft., the difference being only 39 ft.: the mean of these numbers is given above. 
i Time of Flight Average Velocity. 
“47 . 1480 ft. 
Distance, 
220 yards, 
, OL 1345 “* 1116 * 
ee 
