168 
SHORT NOTES ON THE 18-PR. MX. GUN. 
These cones will give the fronts covered in terms of the distance of 
the opening of the shell as follows:— 
Tor 8° . *14 of the distance. 
, 9° . T5 
-10°... -17 
The angles of descent are only approximate, but must be near 
enough the truth for all practical purposes. 
The angles of ascent after graze are not given, but from the greater 
length of the projectile they are most probably even greater in propor¬ 
tion than those suggested by the writer for the 16-pr. guns. It is to 
be regretted that this factor, and that of the retardation due to graze, 
have not been ascertained, as both must be stated approximately before 
the path and power of the bullets of the shrapnel fired with percussion 
fuzes can be known. 
The two columns of increase and decrease of range by elevation, and 
of the alteration of the points of impact vertically, might with 
advantage be given in 3', not 5', as the former is the division of the 
tangent scale. In addition, the vertical heights due to 10 yds. in range 
might be given for each angle of descent. The latter would be of 
great value in solving practical questions. For instance, firing at a gun 
detachment 2000 yds. distant, the shell are judged to strike 30 yds. 
beyond: do they pass over the heads of the men or not ? The value 
of 10 yds. would appear in the table as 2*63 ft. The shell, therefore, 
is 7*9 ft. above plane ; in other words, just too high. Again, a shrapnel 
with time fuze is judged to burst 100 yds. short at the same range, and 
30ft. above plane: is this a good shell? Yes; 26*3ft. is the height 
due to the angle of descent, so that 30 ft. above plane is very little 
below what would be the trajectory of the shell which would strike the 
centre of a target of the ordinary height. 
Short extracts from the report of the practice of “A” Batt., “A ,} 
Bde., B.H.A., at Okehampton, are appended, with a view of showing 
what was done with the gun at practical targets under, as nearly as 
possible, service conditions. It is not pretended either that the 
practice was very good in itself, when the great accuracy attainable by 
the weapon is considered, or that the questions proposed for each day's 
practice were in any way conclusively settled. Simply it is hoped 
that the description may prove interesting, as being one of the first 
experiences of an entirely new gun, and especially that it may lead the 
way to further experiment in practical directions, with a view of 
settling some vexed questions as regards the best projectile and fuze 
under varying conditions. 
OKEHAMPioff, 28. 8. 79. 
Targets Employed . 
No. 1 Target .—A dummy gun and limber with detachment on the crest of a 
gentle slope. The gun retired so that only half the wheels were seen from the 
battery, the limber almost invisible. 
No. 2 Target .—Similar to No. 1 in every respect. 
