64 A CALCULATION OF PROBABILITY OF FIRE. 
TABLE XIII. 
Values of WM. 
Ranges 1000 2000 3000 4000 5000 6000 
F. C. corr". 
100 122 147 194 250 309 371 
75 115 WA 147 182 226 271 
50 112 110 127 155 189 226 
25 109 99 104 120 144 172 
0) 108 95 95 106 125 150 
The values of V are found in a similar way. 
ABN TPL IN TEAS IN IS seoonoonnosbeatost ube sebacone (6), 
where A,7’ is the width of the 50 per cent. zone. 
A,P is estimated at ‘1 per cent. of range (001). 
AWS = da x 2 V2, da=-2 per cent. of range. 
. 1 . ° . ° 
f,=time of flight, 4, time taken to traverse 1° of arc; omitting 
intermediate steps the result is 
TABLE XIV. 
Values of UN. 
Ranges 1000 2000 3000 4000 5000 6000 
F. C.’s corr’. 
2° Ti 23 34 46 58 69 
1° 45’ 10 20 30 40 50 60 
T° 30’ 9 17 27 35 48 52 
1° 15’ 7 14 22 29 36 43 
i 6 12 18 24 30 36 
45! 4 9 14 19 24 29 
30’ 3 fa 10 14 18 22, 
15’ 2 5 8 10 13 16 
0 2 4 6 9 Il 14 
Example of use: gun and objective as in tables; direction of advance 
$= 30°; Range 5000 yds.; F. C.’s correction 75 yds. and 15’. 
A=68. B=465. M=226. N=13. 
A 68 ae 
Waa 3 referred to probability table=16 per cent. 
t= <8 % ~ =98 per cent. 
98 
“16 
588 
98 
