3 
Eeample I—At the chief artillery polygon when firing on 29th February, 1894, 
from the 6-inch Q.F. gun of Canet, 50 calibres in length, with 272 1bs. of Ox- 
tensk smokeless powder, velocities were measured at two points of the trajectory. 
The distances from the muzzle were 
«, = 89'6 metres, mean velocity v7, = 785°9 m/s (2579 feet per second), 
H=HOOD x ie » Vg= 745'2 m/s (2445 feet per second). 
We require to determine A in the formula ! 
Ces tt Woh i) 
(2k)? “a “dX ° 1000 * 
The weight of projectile P = 43 kg. (105 lbs. Russian) 
», calibre a 2R = 0°1524 metres (6 inches). 
The firing was carried out at a temperature of 74° C. and barometric pressure 
757-4™™ ; from this and the table, inserted in Appendix I. to my “ Exterior 
Ballistics,’ we shall find 
Denoting by C, the value of C for \=1, we shall obtain 
log, C, = +2265. 
In consequence of the small angle of projection, we can put a cos 0=1, also 
a= 1 (Appendix I., “‘ Exterior Ballistics,” p. 19) so that 
= a = D(v.) — D(v). 
From the appended table we shall find 
Dw)= —4307 
D(v,)= —238'2 
D (vg) —D(v,)= —192°7; 
from the expression 
Vg — Xy 
=] Dene 
we shall obtain 
KS 12S 
The projectiles, intended for Canet’s gun, have a greater length of the head (about 
1°75 calibres) than those, for which were found the expressions for the air resist- 
ances, cited in No. I; the length of the heads of the latter were about 1°30 calibres 
(here X = 1). 
Example II.—To determine the tabular data for the projectile, fired from Canet’s 
6-inch gun at the range X = 2000 sajenes, we have 
P =43°0 kgs. (105 lbs. Russian) 
2h = 0'1524 metres (6 inches) 
™= 1 
™ 
w= 7728 
initial velocity v = 792°5 m/s (2600 f/s). 
From the formule of my “Exterior Ballistics’ (Appendix I., p. 46) em- 
ploying the attached small table and the tables of Lieut.-Colonel Langeldsheld, we 
can calculate the required data. 
We have 
log C= °3810 
and from the formula 
; ; p} 
sin 2 ¢) = es { 1+ (9-072) =} 
v Cc 
1 Zabudski. Exterior Ballistics. Part II., p. 10. 
