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MINUTES OF PROCEEDINGS OE 
having the experience we possess of the successful accomplishment of what only a 
few years ago were regarded as impossibilities in the construction of iron-clads, it 
would be folly to set a limit to the results that will be attained in the future. The 
Admiralty have long been in possession of a design for a turret-ship with sides 
plated with 15-inch armour, and turrets with 18-inch armour. I have also prepared 
outline designs, not on extravagant dimensions, to carry 20-inch armour, both on 
broadsides and on turrets.” 
Mr. Reed also quotes from Captain Scott, R.N., in a foot note, page 
68 :— 
“At the Boyal United Service Institution, in 1863, Captain Scott made the 
following interesting remarks :—‘ The size of the gun is of vast importance—more 
than is generally assigned to it—and for this reason : 20 guns, each a 1-pr., are 
fired at a target l^ins. thick, and produce no effect; one gun, a 20-pr., is fired 
and smashes it; the velocities in both cases being equal, in both cases the same 
amount of metal is used; and on this principle an official record of experiments at 
Portsmouth states that one 68-pr. produced more destruction than five 32-prs. 
Arguing thus, it appears that one 150-pr. is more effective than ten 68-prs., one 
330-pr. is equal to seven 150-prs., and a broadside of three 330-prs. is more 
destructive than 10^ c Warriors/ In this last statement the * Warrior’s ’ broadside 
is taken at twenty 68-prs.’ ” 
Arguing thus, I may say that a ship carrying two 1200-prs. would 
be nearly equal to one-half of the British Navy. 
II. The present Systems of Gun Manufacture . 
A very heavy gun, therefore, being necessary, let us examine the 
sufficiency of the present systems for producing it. 
1. Preliminary Remarks. 
a. Longitudinal Strain. 
The two great strains to which a gun is subjected are the longitudinal 
and the circumferential. Of these, the latter is undoubtedly the greater, 
but the former is that which has given most trouble to know how to 
meet it. 
Mr. Rigg, C.E., in the end of 1867, read “A paper on the connexion 
between the Shape of Heavy Guns and their Durability,” before the 
Society of Engineers, in which he shows that the mass of the breech 
is of great importance in meeting the difficulty. 
He says, at page 3 :— 
tc If the breech, or that portion of the gun behind the base of the bore, be heavy, 
it opposes a considerable resistance to the shot, absorbs the force of the blow, and 
so reduces the longitudinal strain upon the barrel. If the breech be light in 
weight, the first impact is delivered upon a mass of metal, perhaps not greater 
than the shot itself. The breech in this case does not absorb the blow, but 
transmits it at once to the barrel. Time is not given for so heavy a mass to begin 
its recoil; the longitudinal strain is greater than the tenacity of the metal will bear, 
and fracture is inevitable. It may happen that the breech is blown off, or that 
the barrel bursts; but in either case it is the double cross strain that causes great 
