66 A CALCULATION OF PROBABILITY OF FIRE. 
50 yards so quickly; the times given in the first case must be multiplied 
by some factor, and when @=45° this factor is /2 or 14, These 
results have been placed in the second column under ¢=45°. When 
the ship is moving directly across the range is constant and the F. C.’s 
correction is 0. 
Example: a ship advancing direct at 15 knots, Range 5000 yards, 
e=0 
Time 7”, F.C.’s corr.=100, M=309. 
= 45° 
Time 10”, F.C/’scorr.=75, M=226. 
$=90° 
Time o, F. Cs corr.=0, M —125. 
Table of Deflectrons. 
Since 1° subtends 50 yards at a range of 3000, at that range a ship 
moving directly across @ = 90° will traverse 1° of arc in the same time 
that a ship moving directly end on would take to diminish the range by 
50 yards, and if moving obliquely 6=45° the same factor would hold 
good, so that the speed table for range would become a speed table for 
deflection. 
At 1000 yards a vessel moving at the same speed would traverse 1° 
in one-third the time; at 6000 yards in double the time. A speed 
table for deflection can thus be made. 
TaBLE XVIII. 
Table of times taken to traverse 1° of arc at various speeds. 
Speeds 20 knots 15 knots 10 knots 5 knots 
Angles of 
approach @=90° =45° ¢=90° 6=45° f=90° G¢=45° G=90° G=45° 
Times 
Ranges Mt " ” Mu” ” Mt ” “ 
1000 15 2 2:25 _ 3°25 3 4:25 6 85 
2000. 3 4:25 4°75 65 6 8-5 12 16°75 
3000 4:5 6:25 a 10 9 12°5 18 25°25 
4000 6 8:5 9°25 13 12 16°75 24 33°5 
5000 75 10°5 11°75 16°25 15 21 30 42 
6000 9 12°5 14 20 18 25°25 36 50°5 
Taking the same example, 
p=90°, time 112”, F. Cs corr. 1°, W=30, 
p=" ” 163, ” 45, N=24, 
p=0, sf 0, W=11. 
