AUTO-SIGHTS. 
439 
So also, if AgR denotes the error (—) is range R, when the pivot 
leans backward 4', 
A 2 R _ 4 x /3 2 ' __ 4 /? 
R (M + 4) (ft + M) “ (M + 4) (fi + M) 
This from the Range Table of the 6 -in. Q.F. gun, Muzzle Velocity, 
1,882 feet per second. 
Range. 1000 yards. 
2000 yards. 
3000 yards. 
4000 yards. 
p 
57' 
138' 
258' 
404' 
M = 1146 ~ 
J X 
57' 
29' 
19' 
14' 
J3 + M 
114' 
167' 
277' 
418' 
M - 4 
53' 
25' 
15' 
10 ' 
M + 4 
61' 
33' 
23' 
18' 
I—l 
O 
O 
sf 
1 5^ 
3.7 % 
13°/ 0 
25% 
38% 
400 j 8 
~~ (M-4)G3 + Mj 
A, h 
37 yds (33) 260 yds(278) 
75G yds (752) 1520 yds (1512) 
<1 
O 
O 
■— 1 
8 .S°/ 0 - 
10 % 
16% 
21 % 
400 p 
~ (M + 4)(/3 + M) 
A* h 
33yds (31) 200yds(200) 480yds(474) 840yds(833) 
The agreement between these results and those given by the author 
is sufficiently close for practical purposes. 
Astronomers are careful to give the corrections required for errors of 
adjustment in their instruments, so gunners need not be afraid to make 
a similar careful survey of the corrections unavoidable in manufacture, 
for such delicate adjustments as those required with automatic sights. 
I think the author should examine explicitly the error on a vertical 
target due to want of level of the base-plate, as this error is of more 
practical importance than the error of range. 
This vertical error is practically the author’s TP in his Fig. I ; and 
Fig. 4. 
