160 
SHOUT NOTES ON PllOEESSIONAL SUBJECTS. 
end of the wedge a ring handle is provided, to be used in the event of the “ carry¬ 
ing screw ” getting out of order. A chain attached to the wedge, and also to the 
gun, regulates the distance to which the former can be withdrawn. 
The wrench is 20 ins. long, and available both for the “carrying screw” and 
also for the “wedge screw.” The wedge can be worked by one or two men, but in 
the event of this power being insufficient, a piece of cast-iron gas-piping is put on 
the wrench to increase the leverage. 
Loading-Box, —The withdrawal of the wedge admits of the insertion of a 
“ loading-box ” through the end of the breech, the front end touching the breech 
ring, the rear end being rounded off. It is a tube of cast steel, and is kept in its 
proper position during loading by two latches, which turn on pivots in the breech 
and “ catch ” against two bearer pins. It is probable that a “ shell ” or half¬ 
cylinder will be introduced to supersede this “ box,” which will have the advantage 
of being lighter. 
Vent-Bush. —The vent-bush passes through the wedge in prolongation of the axis 
of the bore, when the breech is closed, to avoid weakening the gun. It is of steel, 
having a copper ring in front of it; this ring can be renewed when worn out. 
The bush is somewhat thicker in its front part than elsewhere, to secure its 
position ; its rear end is closed by a piece of metal working in a concavity in the 
breech-piece, on a pivot. This has a slot cut in it to take the friction bar of the 
tube when placed in the vent. 
Sights.— The gun is provided with two fore-sights and tangent scales, the latter 
graduated in degrees up to 15°. 
Projectiles. —The projectiles provided for this gun are chilled and common shells, 
2J calibres = 20 ins., the head being 1*3. 
Chilled Shell.— -1*3 of a calibre, the rounding of which is obtained by a circle 
whose radius equals twice the diameter of the shell without the lead coating. Its 
bursting charge is 2’421bs., and the length of the hollow is limited so as to leave 
the whole of the head solid. The base is closed as in the British service, with the 
exception that the plug is provided with a ring by which the shell is hooked to the 
tackle in raising it. Tor moving the shell a short rope is provided, having a hook 
at one end and an eye at the other. There is a loop in the rope which is passed 
over the point of the shell when the hook is attached to the base ring. 
Common Shell. —The common shell has also a length of 2-J calibres, of which one 
is that of the head. There are two extractor holes in the head, to enable it to be 
lifted by means of a clip. 
The burster is 11 lbs. 
Tor facility of fabrication, a hole is made in the base, which is filled up by a left- 
handed screw plug. 
Cartridge .—The cartridge, 37Jibs., contains 23J layers of hexagonal prisms, 
19 in each layer, or 447 prisms, and is 24-2 ins. in length. The material of the 
cartridge is silk. The 31-lb. cartridge has 368 prisms, and is 20 ins* in length. 
The cartridges have, therefore, hexagonal form, with the edges rounded off. 
