126 REPORT—1852. 
bar of iron rolled upon the mandril, in a spiral direction, and then welded by re- 
peated beatings from the muzzle to the breech. Others were differently constructed, 
by welding the bars longitudinally, in the'line of the barrel, and not in the spiral di- 
rection adopted in the former process. Now the whole is welded at one heat, and 
that through a series of grooves in the iron rollers, specially adapted for the purpose. 
This, with other improvements, has rendered the manufacture of rifles and other 
arms a matter of much greater certainty and security than at any former period. 
Admitting the advantages peculiar to this manufacture, it does not affect the prin- 
ciple of the rifle itself, in which there is no alteration, but in every respect similar, 
even to the spiral grooves, which he believes are not altered, but are the same 
as in the old rifle. This being the case, it has been a question of much interest to 
know wherein consists the great difference in the practice with the new rifle, as com- 
pared with that of the old one. It is not in the gun, and must therefore be in the 
ball, or that part of the charge which generates the projectile force. But, in fact, the 
improvement consists entirely in the form of the ball, which is made conical, with a 
hollow recess at the base, into which a metallic plug is thrust by the discharge. The 
plug is so constructed, as that when driven into the ball, it compresses the outer edges 
against the sides of the barrel, and at the same time forces a portion of the lead, 
from its ductility, to enter the groove, and to give the ball, when discharged, that 
revolving motion which carries with such unerring certainty to the mark. In the 
practice with one of those rifles on the marshes at Woolwich, the following results 
were obtained. Out of twelve rounds, at a distance of 700 yards, as near as Mr. Fair- 
bairn can remember, only one bullet missed the target, and the remaining eleven 
rounds were scattered within distances of about six inches to four feet from the bull’s 
eye. At 800 yards threeshotsmissed the target, and the remaining nine wentthrough the 
boards, two inches thick, and lodged themselves in the mounds behind, at a distance 
of about twenty yards. The same results were obtained from a distance of 900 yards, 
and at 1000 yards there were very few of the bullets but what entered the target. 
In these experiments the end of the rifle was supported upon a triangular standard, 
and the greatest precision was observed in fixing the sight, which is graduated 
to a scale in the ratio of the distance, varying from 100 to 1000 yards, which 
latter may be considered the range of this destructive instrument. 
On Improvements made in the Harbour of Belfast. 
By Rosert Garrett, CL. 
This paper described the situation of the town of Belfast on the River Lagan, at 
its junction with that extensive inlet known as Belfast Lough, and stated that the 
courses of the tides do not tend to the formation of the shoals and bars so formidable 
at many harbour entrances. It appears there are fourteen miles square of good an- 
chorage ground, and from two to ten fathoms of water. The particulars of the river 
and the Lough, and the various engineering additions for accommodation were then 
detailed—from 1720, when the first quay wall was built, and 1785, which marked 
the commencement of the progress which has continued to the present time. The 
designs suggested for the improvement of the harbour by Messrs. Rennie, Telford, 
Cubitt, &c. were described and compared with that given by Messrs. Walker and 
Burges, attention being in particular directed to the manner in which the tidal action 
had been taken advantage of in the latter design, now so successfully carried out into 
execution by Mr. Smith, the Resident Engineer to the Harbour Commissioners. 
On Malleable Iron for Beams or Girders. 
By Tuomas Murray Grapstone, CLE. of Belfast. 
This paper pointed out the difference between cast and wrought iron for beams or 
girders; it was shown that cast iron from its extreme brittleness was unsafe even far 
below the test usually applied to it, especially where any sudden impact or force was 
necessary ; that as the nature of the metal was changed from cast to a malleable state, 
its power of bearing tension in the latter condition was increased more than four-fold, 
while its resistance to compression was not sensibly diminished ; that in consequence 
of this increased strength, the lower webs of the wrought iron girder could be propor- 

