MOUNTINGS FOR COAST ARTILLERY. 
545 
marked on the arc and indicator respectively. The gun can then be 
brought into either loading position by the training and elevating 
numbers working at the same time. I consider that a round a minute 
ought to be attainable. 
Comparing this design with that of Mark II. (Plate V.), I think it 
will be admitted that, in dealing with such a gun as the Mark IX# 
9*2-in., the minimum of size and the maximum of handiness have 
almost been attained. If this mounting proves successful, it will, I 
believe, become typical, thus superseding the earlier (Mark III.) 
design above described. 
Y.—64n. H.P. experimental (Plate VII.). 
The principal drawbacks to the service H.P. mountings arise from 
two causes, the high air pressure and the rocking ram cylinders. To 
hold a pressure of 1250 lb. requires special skill in care and packing; 
at the same time, the rocking cylinder is eminently unfavourable to 
the gland. It was necessary, therefore, to seek some other mechanical 
arrangement, and to lower the working pressure. 
Plate VII. shows such an arrangement. The head of the ram (A) 
is trunnioned into links (B C) forming with B E and C D a three-bar 
system, giving practically rectilinear motion. The action on recoil 
will be evident from the figure. The ram descends vertically, dis¬ 
placing its own volume and reducing the air space (F F). 1 The 
pressure gun down is 2501b., falling to 1701b. when the gun is in the 
firing position. 
An arc (H), attached to the elevator, moves a ratchet-wheel in con¬ 
nection with a friction clutch. The gun is thus held down after recoil 
and freed by releasing the clutch. There are, therefore, no valves of 
any kind, and the only part of the mounting requiring special attention 
is the packing of the gland (J), which has to retain a maximum 
pressure, gun up, of 1701b. Perfectly free access to the gland is 
provided from the well (W), and I do not think that any difficulty 
will be experienced in keeping this mounting in working order. Both 
ram and cylinder are made of metal with a view to avoid the deposit of 
brown mud which collects in the service steel cylinders. 
The Q.F. gun having no trunnions, is placed in a cradle (L) attached 
to the lug. 
A carriage sight, built up from the brackets, is provided on each side, 
and the sighting platforms (K) have elevating and training gear in 
addition to that worked from the emplacement floor. Further provision 
is made for the employment of straight-edge sights attached to the 
gun cradle. Thus there are altogether four sights and by means of a 
special indicator elevation can be given from the emplacement floor. 
The gun can be laid when down from either sighting platform, and 
corrected immediately on rising by the laying number, who has com¬ 
plete control, and can fire with his eye along the sight. 
The shield, of little practical use and very objectionable in 
1 Viewed as an H.P. arrangement, this is similar in principle to the 6-in. Indian patters 
mounting and an experimental 6-in. proposed by my predecessor. Both haye worked well. 
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