336 
New garrison carriages. 
I .—The Carriage. 
(Weight, complete, 120 cwt.; tonnage, 4'995 tons.) 
The carriage is of “ double-plate ^ construction, the frames of the 
brackets being of wrought-iron. The latter are formed each with a 
slot or recess in it, for the trunnion-bearing to slide in, the inner 
bracket-plate being cut away over the slot and the outer strengthened. 
The trunnion-bearing is a solid block of wrought-iron, without metal 
lining, in which the trunnion is held by a capsquare with two double- 
nutted bolts. 
The brackets are secured in the usual manner upon a bottom plate, 
and connected by three low transoms. The former has a slot cut in it 
to receive a hydraulic lift, which, acting under the trunnion-coil of the 
gun, raises or lowers the latter to any level required. The lift is 
immediately supported by two strengthening plates, riveted one on 
each side of the slot) and secured by four small movable plates and two 
clips. 
The hydraulic arrangement^ consists of a cylinder, A (Fig. II.), and 
ram, B, of wrought-iron, with a reservoir, C, of cast-iron, which contains 
the pump, D, of metal. The ram has a cradle, b, which, when the lift is 
in action, bears against a patch on the gun. The pump is double¬ 
acting, as follows:—Its plunger, cl, is worked by the camb, e, and cross 
shaft, f —the latter passing through the brackets of the carriage and 
having a lever upon each end. When the plunger is raised, water 
(mixed with methylated spirit) is drawn in at the inlet valve g , while 
the water already above it is forced by the passages h and i to the ram, 
its pressure at the same time keeping the outlet valve, h, closed. When 
the plunger is lowered, the pressure on the water under it closes the 
inlet valve, opens the outlet valve, and sends a flow by the passage, i, 
to the ram, and also by h to the space above the piston. Thus in both 
up and down stroke, pressure is transmitted to the ram, and work is 
done in raising the gun. In order to lower the latter, it is only 
necessary to permit the water to flow back to the reservoir from the 
cylinder, through the passage, m, provided for the purpose, by un¬ 
screwing the lowering plug, L; this is done by pushing a lever attached 
to the crank, l , and passing out through the left bracket of the carriage. 
N and 0 are plugs which close respectively the filling and emptying 
hole of the reservoir. 
The hydraulic lift is supplemented by a screw lift, upon which the 
gun is intended to rest when fired, and not upon the former.f It 
* This lifting arrangement, designed and made in the Royal Carriage Department, is deserving 
of special attention, for its compactness and the readiness with which it can he removed, as a whole, 
from the carriage, or any part be got at for repair without removal. In other such lifts—for 
example, those used in the navy—the ram and pump are separate and connected by tubes ; the 
connections being parts of weakness, while the tubes themselves necessitate an increased expen¬ 
diture of labor. 
f There is nothing in the hydraulic lift itself to forbid the gun being fired resting upon it, and 
upon two occasions this has been done; but the carriage is not constructed to take the strain of 
discharge upon the bottom plate, to which it would then be transmitted from the ram. 
In naval muzzle-pivoting carriages movable blocks are used instead of screws, to support the 
