A CALCULATION OF PROBABILITY OF FIRE. 
Value of 
F. C.’s corr™. 25 yds. 50 yds. 75 yds. 100 yds. 
[2 
63 
100 
Ida? 
6000 
3600 
= = 17 1 16 4 
From (5) 
F.C.’s corr. 0 25 50 75 
Vi we = @ Bla? Bde? 4 dla 
Since dX is 1 per cent. of the range, we get the following value 
for dX?: 
Ranges 1000 2000 3000 4000 5000 
IDS. aX? = 100 400 900 1600 2500 
Values of 
From VIII. and IX. 
TABLE X. 
F. C.’s corr™. 100 75 50 25 
Ranges 
1000 yds. 900 455 300 150 
2000. ,, 3600 1822 1200 600. 
3000 ,, 8100 4100 2700 1350 
4000 ,, 14400 7288 4800 2400 
5000 _,, 22500 11388 7500 3750 
6000 _,, 32400 16400 10800 5400. 
SQoe2ee 
AT is the length of the 50 per cent. zone and can be found from the 
Range tables. 
found. 
TABLE XI. TABLE XII. 
yds. AT AT? AP AP’ 
1000 23 529 48 2464 
2000 18 324. 40:5 1640 
3000 17 289 33-5 1122 
4000 21 44] 27 729 
5000 29 841 225 506 
6000 40 1600 19°5 380 
AP is the value of 24’ error at various ranges and can also be 
By adding these three values and doubling their square root we get 
the value of M as shewn in the table. 
9 
