256 
MINUTES OF PEOCEEDINGS OF 
Dockyard. The details of construction of this wrought-iron carriage are 
very different from those of the wooden 68-pr. I have just described, but the 
principle of muzzle-pivoting remains the same. With the aid of some 
diagrams I have had prepared, I will endeavour to describe this carriage to 
you. Here we have, Plate II. Pig. 9, a side view of the carriage on 
its slide, with the gun mounted, and shown at elevation and depression, in 
the port of the cupola; as I before stated, in this case, owing to the interior 
diameter of the cupola being only 16 ft. 6 in., and the gun being 11 ft. 
long, in order to leave reasonable room for recoil, I have been obliged to 
pivot the gun 1 ft. in from the muzzle, which causes the port to be slightly 
larger than if I had pivoted it exactly at the muzzle. This carriage is con¬ 
structed in frames of 5 in. angle iron, •§■ in. thick; the bottom is of boiler 
plate lin. thick; the sides are of f in. boiler plate, 4ft. 11 in. high, 7 ft. 
long; the transoms are also of J in. plate; the different stays are of f in. 
T iron. 
Now to obtain muzzle, or rather 1 ft. from muzzle-pivoting, I describe 
my two concentric circles with radii of 5 ft. 2 in., and 8 ft. f in. (see Pigs. 10 
and 11, Plate I.), and between them I place a girder built of strong T iron, 
and boiler plate, capable of supporting many tons. In front and rear this 
girder is bounded by arcs, described with the same radii as the concentric 
guide pieces. This being done with both brackets, these girders, which you 
see are provided with trunnion-holes, are tied together with a strong iron 
band, fitted to the shape of the gun, and so form a moveable cradle for the 
gun to rest in. The section of the arcs in front and rear of the girders is 
of this form h, the projecting portion being toothed, and the section of the 
concentric guide pieces is i so that one section fits exactly into the other. 
That portion of the angle iron between the tops of the concentric guide 
pieces is cut away (the bracket being proportionately strengthened on the 
outside), and the cradle is lowered down between the guide pieces, till it 
rests on the pinions front and rear; these pinions are worked similarly to 
those in the wooden carriage, with the addition of a toothed wheel to increase 
the power. The sides are secured to the bottom by means of angle iron and 
rivets, and are tied together by two transoms, which are made as deep as 
possible, and hollowed out in the way of gun. As the guide pieces have to 
sustain the shock of the discharge of the gun, they are supported by strong 
stays of T iron; the whole of the pinion wheels and shafts work in metal 
bearings, to prevent being set fast, while means are provided for getting 
readily at all parts for the purpose of cleaning, oiling, and repair. This 
carriage works upon a slide (Fig. 13), which is, as long as the cupola will 
admit; it is constructed of T iron and boiler plate, the lower piece of T iron 
is bolted to the floor of the cupola; the slope of the side is-4°. 
As a breeching rope would be much in the way, a breast chain is sub¬ 
stituted for it, to limit the recoil, while a rack on each side of the slide and 
pauls upon the sides of the carriage, preclude the possibility of the gun 
running out from a sudden lurch, or any other cause. 
The carriage will be run in by an arrangement of tackle, devised by 
Capt. Coles, and already at work in the cupolas of the “ Royal Sovereign.” 
Buffers constructed of india-rubber rings are placed on the front of the 
carriage, to lessen the concussion when the gun is run out. 
