par Jean-Louis Vial About French units of measure: Former French units of measure are conserved in the text because it's impossible to give them a real translation. Sometime they are converted in meter or centimetre and their value are placed between brackets. ligne = 0,225 cm pouce = 2,707 cm pied = 32,5 cm pas = 2 pieds 6 pouces = 97,5 cm toise = 6 pieds = 195 cm The regulation of 1732: The siege artillery was composed of heavy cannons with large calibers 33, 24 and16-pounder guns and mortar pieces. The mortar was a piece that fired with a weak powder charge a spherical shell filled with a powder bursting charge. The shell projected along a curve path over the defence was designed to burst into many ragged around its fall point, dispersing personnels of defence and allowing assailants to advance to short distances. On the same principle the pierrier projected against the enemy a basket filled with stones, but with an efficiency well inferior than mortar they were less numerous. In 1732, Lavallière in his reform of the artillery precised the dimensions that casters had to follow for the five pieces of the regulation. - 8-pouces mortar with a cylindrical chamber containing a powder charge of 1 3/4 pounds. - 12-pouces mortar with a cylindrical chamber containing a powder charge of 51/2 pounds. - 12-pouces mortar with a pear chamber containing a powder charge of 12 pounds. -12-pouces mortar with a pear chamber containing a powder charge of 5 1/2 pounds. -15-pouces "pierrier" with a curtailed cone chamber containing a powder charge of 2 1/2 pounds.   Mortier de 12 pouces chambre cylindrique de 5 1/2 livres Mortier de 12 pouces chambre poire de 12 livres mortier de 8 pouces pierrier de 15 pouces   Jean-Louis Vial