440 
AUTO-SIGHTS. 
in Fig. 4 , TP 1 = i 6// 1 feet, where t x is the extra time of flight for the 
range GC ; while TP 2 = i 6// 2 feet, where / 2 is the defect in time of flight 
for the range GB, t denoting the time of flight for the real range GT. 
GC _ sin M _ M GB __ M 1146 h. 
GT - sin (M- 4) “ M-4 ; GT ~ M + 4 ’ R 
This vertical error becomes serious at ranges of 3000 yds. and over ; 
but I do not think it was ever intended that the automatic sight should 
be employed at these long ranges with such a small command as 50 
feet. The correction for tide level would now become of equal impor¬ 
tance ; and Major Dunlop points out that the two corrections for tide 
level and for level of base plate, can be carried out in the same manner. 
Range G T. 
1000 yards. 
2000 yards. 
3000 yards. 
4000 yards. 
M 
67 
29 
19 
14 
M-4* 
63 
25 
15 
10 
GC 
— x 1000 
29 x 2000 
I 9 v 3O00 
14 
x x 4000 
53 
25 
25 
10 
= 1075 yds. 
= 2320 
= 3800 
= 5603 
(From Range Table) t -f t\ 
1.83s 
4.43 
8-25 
13-4 
t 
1.73 
3-73 
610 
8-0 
t\ 
0-1 
0.7 
2-15 
5*4 
log t 
0-2380 
0-5717 
0-7853 
09031 
log 
1-0000 
1-8451 
4-3324 
0-7324 
log \9 — log 16 
1-2041 
1-2041 
1-2041 
1-2041 
log TP X 
0-4421 
1-6209 
2-3218 
2-8396 
TP X 
2-768 ft. 
41-78 
209-8 
691-1 ft. 
M 
57 
29 
19 
14 
M + 4 
61 
33 
23 
18 
GB 
&J v 1 non 
29 x 2000 
19 x 3000 
14 x 4000 
_6 f x 1000 
33 
23 
18 
= 935 yards. 
= 1760 yards. 
2500 yards. 
3100 yards. 
(From Range Table) t—1. 2 
1-63 
3-17 
4-86 
6-36 
t 
1-73 
3-73 
6-10 
8-0 
h 
0-1 
0-66 
1-24 
0-64 
log t 
0-2380 
0-6717 
0-7853 
1-9031 
log * 2 
1-0000 
1-7482 
0-0934 
0-2148 
log 10 
1-2041 
1-2041 
1-2041 
1-2041 
log TP 2 
0-4421 
1-6240 
2-0828 
2-3220 
tb 2 
2-765 
33-42 
121-1 
209-9 ft. 
