549 
LAYING- WITH A CLINOMETER. 
,/). 
BT 
CAPTAIN E. E. NORRIS, R. A. 
A series of very interesting papers have appeared during the past year 
on this and kindred subjects* Major Reir wrote in April, 1896, Capt. 
Crampton discussed Clinometers in October, and Capt. Guinness took 
the other side in February, and advocated the direct method of laying. 
No one however has touched on a weak point which seems very 
serious, uuless met in some such manner as I shall propose later. The 
drill book touches it, on page 95, as follows;— a It is desirable to have 
the guns of a battery as nearly as possible on the same level. (That 
is when laying with the Clinometer). If this is impossible, the battery 
commander should order the necessary correction, which should be 
given by sections/ 1 But how many commanders have grasped the force 
of this short paragraph, and how fmany could say off hand what the 
"necessary correction n is?. With this point I wish to deal, first by 
showing that often corrections would be very necessary, and next, what 
they should be in various cases. The consideration seldom arises on a 
flat barrack square, but how often could we hope to have on service, 
both an horizontal position and an horizontal target ?. Seldom, I think. 
Throughout this paper, I mean by a target, an object 100 yards long, 
where the battery and target are in two parallel vertical planes. When 
speaking of the clinometer, I mean the spirit-level parallel to the gun, 
and its adjusting gear found on the last pattern Scott sight. Further¬ 
more I assume that the fir© is accurately distributed over the target. 
Now let us consider a case. Range 2000 yards. 
No. 1 gun and right of target in the same horizontal plane. 
No, 6 gun, 10 feet above No. 1. 
Left of target, 10 feet below the right of the target. 
Seen from the rear of the battery, the view (ignoring perspective) 
would be like this:— 
Fm. i. 
A. B. No. 6 and No. 1 guns, 5, 4, 8, and 2 omitted, 
G. B. Left and right of target invisible from battery,^ 
D. E. Crest of hill screening the battery* 
H. H. Horizontal plane through B. 
TOli, XXIY. 
11 , 
