THE ROYAL ARTILLERY INSTITUTION. 
349 
The upright bar is divided off into various'lengths, giving the heights of 
scale for low and high angle fire of the different projectiles; similarly, the 
amount of allowance for deflection is given by the divisions on the traversing 
bar. In both cases, above the divisions on the upright and traversing bars, 
the number of hundreds of yards is stamped, shewing the ranges to which 
the vertical and horizontal lengths are applicable. 
Upon the front* of the upright or tangent-bar is a scale marked c.l., 
used in firing common shells at low angles at ranges from 170 to 1700 
yards; a second marked c.h. used in firing the same projectile at high 
angles between 400 and 900 yards; and a third marked s.l., used in firing 
shrapnel shells at low angles from 250 to 1250 yards. 
On the rear side of the scale is a continuationf of the scale used in firing 
common shell at low angles from 1700 to 2500 yards, and further the 
continuation of the scale for firing the same projectile at high angles from 
900 to 1500 yards. All the letters above-mentioned are engraved on the 
slider in prolongation of the scales they refer to. 
On the front side of the traversing bar is a derivation scale marked c.l., 
used in firing common and shrapnel shells at low angles, and a second 
scale marked c.h., used in firing the former projectile at high angles. 
On the back of the traversing bar is the continuation of both these 
scales. 
The divisions on the derivation scales used in firing common and shrapnel 
shells at low angles are given for every 400 yards, those used in firing 
common shell at high angles for every 200 yards. 
The base of the 3-pr. tangent scale is marked “ 3-pr. m.g.” 
The tangent scale is carried in a leather case, slung over the right 
shoulder of the pointsman, by a lanyard passing through the lug at the 
base of the tangent scale; the lanyard is sufficiently long to allow of the 
tangent scale being used without unslinging it. On the march, the tangent 
scale is carried in the right-hand cartouche of the gun-mule. 
The tangent scale and vent bit are kept in one leather case which has 
two sheaves appropriate thereto, and a body strap for buckling it to the 
pointsman. 
The service sponge (Tig. 5) consists of a staff, the sponge head, 
strap staple, and the rammer head l of stout sheet^iron; the last is 
used in ramming home the cartridge and projectile and in extracting 
common and shrapnel shells; for this purpose the circumference is cut out 
in two places a)% these cuts fit and grip the two drifts on the nose of the 
projectile. 
The sponge when not in use is strapped to the cheek of the carriage. 
The drill-sponge is the same as the above, with the exception that it has 
an ordinary wooden rammer-head in lieu of one of sheet-iron. 
The fuze spanner (Tig. 18) has a pair of jaws to take the nut of the 
fuze, the points of the jaws form two studs. 
* When the lug on the base of the tangent scale is to the left of the upright bar, the side of 
the scale next the eye is the “ front side.” 
f The divisions are calculated with the shorter radius from breech to trunnion sight* 
X Like the bayonet joint. 
[VOL. VI.] 
46 
