THE proof of mortars, according to the ordinance of the 7th of October 1732, ought to be begun by ƒcraping, with an inƒtrument well tempered, all the places where a flaw is ƒuƒpected; and if nothing of that kind is diƒcovered, the proof muƒt be proceeded in, by firing them with as much powder as the chamber will contain.
        For this purpoƒe the mortar is placed upon the ground, with ƒome part of its trunnions ƒunk below the ƒurface, and reƒting on wooden billets, to prevent their being driven in too far; the piece is then fired three times ƒucceƒƒ ively, with bombs of a proper caliber, filled with a mixture of earth and ƒaw-duƒt. The touch-hole is then ƒtopped, and the mortar filled with water, to diƒcover whether there be any crack or flaw through which it can inƒinuate itƒelf. Afterwards the piece is well waƒhed and ƒcraped, and when no flaws or hollows appear, or any other circumƒtance to its prejudice, the mortar is received; on the contrary, when any defects are diƒcovered, which might render it leƒs ƒerviceable, its handles are immediately broken off, and the founder can demand nothing for making it.