200 
MINUTES OE PROCEEDINGS OE 
I believe the results of all these trials would have ended differently had 
the cartridge used with the cast-iron rifled gun been judiciously elongated. 
If the initial velocity of the projectile had been affected by this, the 
addition of a little more powder would have restored any loss, while the 
elongation of the cartridge, by spreading the strain over a greater surface, 
would have considerably reduced the initial strain on the gun, and the 
consequent tendency to burst. 
It is hoped that cast-iron gun barrels may never be employed in this 
country for rifled pieces, but if such should be the case, a trial should be 
given to elongated cartridges, which, there is every reason to believe, will 
have a great effect on the endurance of the gun. Meanwhile, it might be 
worth while to alter the dimensions of the present service cartridge with all 
smooth-bored cast-iron guns. It has been proved that with the 68-pr. 
cartridge an elongation of nearly two inches does not effect the velocity and 
range, and it is evident that the initial strain must be reduced by the use of 
a cartridge 12 inches long instead of 10* 
Experiments to ascertain the effect of the position of the vent on 
initial velocity . 
7. This question has been for a long time in much obscurity, and has 
afforded grounds for many conflicting opinions. No satisfactory experiments 
had ever been made on the subject; for although Hutton and Mordecai 
instituted investigations in this direction, they gave their attention princi¬ 
pally to the effect of the position of the vent on the escape of the fired charge 
through it y and not to its influence on the ignition of the gunpowder.* 
Under these circumstances it was most desirable that the matter should 
be cleared up and set at rest, and in the latter part of 1862, Brigadier-Gen* 
J* H. Lefroy, B.A. submitted the following memorandum on this subject to 
the Ordnance Select Committee, of which body he was then Secretary. 
General Lefroy says :— 
“Piobert remarks” [flours d’ Artillerie, p. 207), “ that experience has 
demonstrated the advantages of the usual position of the vent, namely, 
at the end of the bore, but/ he proceeds, ‘ since the rate of burning of 
the powder has something to do with the most advantageous position to 
give to the vent, it results that experiments made in different countries 
on the position which gives the greatest initial velocity to the projectile 
have not always agreed/ 
“ This qualification shows that there is an ample field for fresh inquiry; 
and since we can now ascertain initial velocities with a facility unknown 
when the above passage was written (1835), and are at the same time seeking 
to modify and control the rate of burning of our powder, it would appear a 
favourable moment for taking up the question, which is new in this country. 
“The general arguments for placing the vent at the bottom of the bore 
are: (1) It is favourable to the complete expulsion of the cartridge. 
(2) The gas first developed has the cubic space occupied by the charge 
* Colonel Boxer’s Treatise on Artillery, p. 61, sec. 158. 
