544 
MOUNTINGS FOR COAST ARTILLERY. 
comparative figures in Plate V. show clearly that the new pattern is 
far simpler and less ponderous than its immediate predecessor, not¬ 
withstanding the fact that the gun is much more powerful. 
IV .—9 '2-in B.L. barbette depression, Mark IV. (Plate YI.). 
The demand for a mounting to give 20° depression, provided an 
opportunity for the proposal of an axial recoil arrangement. The gun 
trunnions are placed in cast-steel sliding pieces, which move in a cast- 
steel cradle built up in four parts—two side and two end pieces, the 
latter being underneath the gun and furnishing attachments for the 
air cylinder (A) and the piston rod head (B) respectively. A sleeve 
(0), formed in two pieces, embraces the gun and furnishes a lug (D) 
below. The buffer cylinder (E) is held by this lug and its rear end 
enters the air cylinder (A) through a liquid gland at F. 
The gun in recoiling drives back the buffer cylinder, which, acting 
like a ram in the air cylinder (A), compresses the air to about 500 lb. 
per sq. inch. The gun is brought up in 3 ft. 6 in. by the buffer, and 
the air pressure in the cylinder immediately runs it out again subject 
to control by a rod attached to the end of the buffer cylinder which, 
enters a hollow in the piston rod. An intensifier in connection with 
the air cylinder keeps the liquid gland in pressure which increases 
during the recoil. The general principle of this recoil arrangement 
was applied by my predecessor to a 10-in. H.P. converted mounting 
at Sheerness, where it has acted well. The pressure in the air 
cylinder with gun run out will be 200 lbs., which should be easily 
retained and can in any case be quickly restored. By means of a small 
hand pump attached to the cylinder (A) two men can easily restore 
lost pressure at the rate of 1 lb. per minute. There is free access 
to the gland by getting inside the cast-iron pedestal. It will be noticed 
that there are no valves or complications, and that, in addition to the 
care of the ordinary buffer gland, it is required only to make a packing 
to retain a working pressure of 200 lb. I believe that this is well 
within the powers of the Garrison Artillery of the present day. 
The pedestal and roller path are the same as those of the 9*2-in. 
barbette mounting previously described; but, in this case, the em¬ 
placement floor is at the level of the top of the pedestal. 
Training and elevating can be performed from the sighting platform 
(H) or from the emplacement level. There are three training stations 
and two elevating stations. A training arc and an elevation] indicator 
are provided. 
Sighting offers no difficulties in the case! of an axial-recoil mount¬ 
ing and an auto-sight with telescope will be provided on the right 
side of the gun. For loading, the projectile can be brought up in a 
lift from which it can be rammed direct into the gun at 10° elevation, 
a sliding tray being provided as applied to the Mark III. barbette. 
The charges brought up in shelves under the projectile can be easily 
handled. As the gun can be trained 90° in 1' 45" by two men without 
any great effort, there is no objection to having alternative lifts, the 
corresponding position of the gun in training and elevation being 
