REMARKS ON THE PROOF OF POWDER BY THE EPROUVETTES.
By eprouvettes or pendulum.
By comparing the results of the proofs by the eprouvettes with those furnished by the cannon pendulum (vide [plate 1], fig. 2 and 3), it will appear that the eprouvettes are entirely useless as instruments for testing the relative projectile force of different kinds of powder, when employed in large charges in a cannon. Powders of little density, or of fine grain, which burn most rapidly, give the highest proof with the eprouvettes, whilst the reverse is nearly true with the cannon.
Real use of eprouvettes.
The only real use of these eprouvettes is to check and verify the uniformity of a current manufacture of powder, where a certain course of operations is intended to be regularly pursued, and where the strength, tested by means of any instrument, should therefore be uniform.
Best proof, by service charges.
The only reliable mode of proving the strength of Gunpowder is, to test it with service charges in the arms for which it is designed; for which purpose the balistic pendulums (vide [plate 3]), are perfectly adapted.
Best proof for small arms.
For the proof of powder for small arms, the small balistic pendulum is a simple, convenient, and accurate instrument.
Common eprouvette.
The common eprouvettes are of no value as instruments for determining the relative force of different kinds of Gunpowder.