344 
MINUTES OF PROCEEDINGS OF 
Resolving tlie velocity of tlie wind parallel and perpendicular to tlie 
line of sight, we have for the portion which affects the range, 
W cos D cos E ; * 
and for the portion which affects the line, 
W sin D . 
Since the wind is assumed to move horizontally, it will not affect the 
height above the earth's surface to which the projectile will rise; and 
therefore the time of flight will remain practically unaffected thereby. 
Supposing the shot to start with a velocity V f and the resolved part 
of the wind's velocity, W cos B cos E, to be in the same direction in 
which the projectile is travelling, then the latter will evidently encounter 
the resistance of the air due to the difference between the two velo¬ 
cities j that is, 
V — W cos J) cos E. 
Should the resolved part of the wind's velocity, W cos B cos E, be 
blowing in the direction opposite to that in which the projectile is 
moving, then the latter will meet with the resistance due to the sum of 
the two velocities; that is, 
V + W cos B cos E. 
That part of our problem which concerns the range, may now be thus 
stated:— 
r W = velocity of wind in feet per second, 
B = angle between direction of wind and line of sight, 
V — muzzle velocity of projectile in feet per second, 
Given ( d = diameter of do. in inches, 
w = weight of do. in pounds, 
t = time of flight in seconds, 
^E = angle of elevation of gun. 
To find the range. 
First, let the resolved part of the wind's velocity be with the projectile. 
Taking Professor Bashforth's work on the “ Motion of Projectiles," 
we turn (for ogival-headed shot) to Table IX., and there look out the 
number of seconds placed against the velocity equal to V— IF cos B cos E. 
Multiplying the given time t (if not known, it can readily be calculated 
d 2 
from other tables in the same book) by —, we add the product to the 
time found in Table IX.; opposite the sum of these times we find the 
velocity remaining when the projectile arrives at the mark. Turning 
now to Table VIII., we find given the distance passed over between 
the muzzle velocity (V—W cos B cos E) and the final velocity as just 
found in Table IX. Calling this distance S, we then divide S by 
d 2 
—, and we have the distance through the air that would be travelled 
w 
* IS being the angle of elevation. 
