430 
MINUTES OF PROCEEDINGS OF 
The matter, however, is not yet settled; platinum-tipped vents, without 
the flange, are under trial. The more powerful the gun, the greater is the 
wear and tear on the vent. Simple copper vents are most satisfactory for 
guns up to a certain size, and in spite of the softness of this metal, many 
think it will answer for very large guns quite as well as a more costly 
material. Indeed the difference in the expense of the various kinds of vents 
used is remarkable. 
£ s. d. 
A 9-inch vent of copper costs . 0 6 3 
„ „ steel, lined with copper . 3 18 0 
/; u i, u and tipped with platinum 16 4 0 
This difficulty about vents is only one of the many which have to be 
overcome before we can obtain heavy guns perfect in every respect. 
(6) In addition to the marks made in lining, and the Royal cypher before 
mentioned, the broad arrow and actual weight are stamped behind the vent, 
and two parallel lines are cut across the vent field to indicate the unrifled 
space. The material of the inner barrel (for example firth's steel), is 
stamped on the face of the muzzle, as is also the number of the steel barrel 
as entered in the registry of manufacture. 
On the left trunnion are— 
the initials R.G.F., the register number of the gun, the numeral signify¬ 
ing its pattern, and the year of proof. The register number is that by 
which the gun is registered in the Department records; it indicates also 
the number of that nature manufactured. With respect to the numeral, 
the word “ pattern 99 was superseded by “ mark/'’ and the construction of 
guns has been designated as follows since 20th April, 1868:— 
Mark. 
1 
( Original construction, to be . 
i.' 
9 -inch .* 
< F, with steel tube and breech-piece ... 
n. j 
> Plate 2. 
i 
C F II. a without breech-piece 
hi. J 
> 
8 -inch . i 
( Original construction . 
i.' 
> 
7 -inch of 7 tons. - 
F I. with breech-piece . 
n. 
> Plate 4. 
n 6-§- ii i 
( F II . 
hi. J 
) 
i 
C Original construction . 
L i 
) 
64-prs .• 
< B pattern. 
ii. 
> Plate 1. 
i 
CD * . 
hi. J 
1 
Guns of Mark II. construction are not numerous, there being only 
twenty-six 9-inch, six 8-inch, two 7-inch of 7 tons, twenty 7-inch of 6| tons, 
and fifty 64-prs.; and all these, with the exception of the 9-inch, were made 
