]8 
SHORT NOTES ON PROFESSIONAL SUBJECTS. 
9-in. gun, No. 329 which, has fired 500 rounds of 431b. charges with wads; with 
that of 9-in. gun. No. 298 which fired 1043 rounds without wads, of these the 
last, 500 were all with the same charge of 43 lbs., and they were fired with a new 
vent made in what had previously been the under side of the gun. The under 
surface which had been scarcely perceptibly marked by the previous 543 rounds, 
now became the upper surface, and both guns started for this comparison on equal 
terms. The following notes shew their further progress :— 
Gun, No. 298, without wads. Gun, No. 329, with wads. 
The present top of the bore, namely grooves 
4, 5, and 6, was the original bottom of bore, and as 
bottom of bore has fired 156 battering rounds, 
charge 42 to 45 lbs., 387 ordinary rounds, 
charge 30 lbs. and under; total 543. There is 
scarcely any perceptible scoring over this portion 
of bore, but groove 2 (now the bottom) is con¬ 
siderably cut along both edges, and the lands 
between 1 and 2, and 2 and 3, are also considerably 
scored. The vent of 298, is 9*75" from end of 
chamber, and in the other case only 1J. 
After 100 rounds :— 
Very decided scoring on grooves 4 and 5, and No scoring whatever, 
on the lands between 4 and 5, and 5 and 1. The 
condition of the bottom (formerly top) unaltered. 
After 200 rounds i — 
The scoring on grooves 4 and 5, and lands 
between them produced by 200 consecutive batter¬ 
ing charges is very materially greater, full twice as 
great as the scoring on grooves 1, 2, and 3, and 
the lands between them, produced by the whole 543 
rounds previously fired. Scoring on grooves 1, 2 , 
and 3, and the lands between them, not perceptibly 
increased. 
After 300 rounds:— 
Scoring on grove 5 much increased, and also On 
tbe lands between 4 and 5, and 5 and 6, so great 
as almost to obscure groove 5, the guttering being 
in places as deep as the groove. The deep part of 
this scoring is along the groove, for about 12", 
after which it is still perceptible, though slight, for The scoring does not ex- 
about 5" further. tend, a decided roughness at 
The impression on groove 2 (now the bottom) the upper part of the bore, 
and the adjacent lands is very slightly increased. 
After 400 rounds :— 
On groove 5 the roughness is extreme, some of The roughness not per- 
the cavities being nearly 0-5" deep, and the loading ceptibly increased, 
edge is quite obliterated, and there are gutters 
A perceptible roughness. 
Roughness a little in¬ 
creased, and beginning to 
assume a reticulated charac¬ 
ter. 
