TREATISE

O N

F I R E - A R M S,

FIRST PART.

Of the Resistance of Fire-arms to the Actionof Powder,

The Metal of which any Fire-arm is made ought to have cer <-tain determined Phyfical Qualities, combined in so jufl a■manner with the Thickness of the Piece , that it may be ableto resist the Explosion of the Powder , without being unneces-sarily heavy and unweiidy.

THE earlier Artillerists, convinced from experienceof the justness of this remark, substituted in the room of ironordnance, guns and mortars cast of Bronze, a metai com-posed of tin and copper; to which they sometimes added aproportion of brass : hoping that this mixture would poflessthe several qualities in which the iron ordnance had proveddefective.

2. Bronze was in qle before the invention of gun-powder.It had long been known that a mixture of tin with copperwas less tenacious and malleable, but harder than pure copper;and that it even became short and brittle, if the tin were intoo great a quantity. Wherefore the two metals were pro-G % portioned