A CALCULATION OF PROBABILITY OF FIRE. 67 
To find A and B in this case, Tables VI. and VII. 
$=90° A=50, p=45° A=575, p=0° A=130, 
»  B=915, ep S6a5: » B=165. 
The percentages can then be found, 
p=90° p= 45° p=0° 
A _ 50 A_o15 A _180 
M125” M226” M~ 309’ 
B _88% B_645 = B_168 
IN BX” iy We? my I © 
_ These values can be worked out and referred to a probability table, 
and the percentage of hits will be found to be 
p= 90° p=45° p=0° 
20°5 per cent., . 11:9 per cent., 16 per cent. 
The following is a table of efficiency worked out in this manner. 
TABLE XIX. 
Table of efficiency or probable percentage of effective shots at a ship 
300’ x 60’ x 15’ from a 6” B. L. gun 100 feet above the sea level, Range 
instrument D.R.F. 
(1) Ship end on advancing or retiring direct, ¢=0. 
Ranges 1000 2000 8000 4000 5000 6000 
Speeds Percentages 
knots percent. percent. per cent. per cent. per cent. per cent. 
5 79 83 67:5 465 24:25 - 16:25 
10 79 82 59 38°5 21 9°75 
15 79 id 59 32°75 16 9°75 
20 78 77 52°25 24°75 12 75 
(2) Advancing or retiring obliquely, ¢ = 45°. 
knots percent. percent. percent. per cent. per cent. per cent. 
5 58 61 49 35 20°5 13 
10 58 59 42°75 30 15°5 86 
15 57 57 37 23°5 ILS) a 
20 54 55 37 19°5 Oe7. 6 
(3) Moving directly across, ¢ = 90°. 
knots percent. percent. percent. percent. per cent. per cent. 
5 55 59 45 31 21 15 
10 55 59 45 31 20:75 13°5 
15 55 59 45 30 20°5 IIL 
20 55 59 45 30 20 9°3 
