The guns will be of the following calibres: one-third of 18 prs.; one-third of 12 prs.; and one-third of 24, 9, and 4 pounders in equal proportions. If the place does not possess any very extraordinary means of defence, it will be very respectably supplied with 800 rounds of ammunition per gun for the two larger calibers, and 900 for each of the others. _Gun Carriages_; one-third more than the number of guns. _Mortars_; about one-fourth the number of guns in the three first classes; and one-fifth or one-sixth in the other classes. Of these two-fifths will be 13 or 10 inch mortars, and the rest of a smaller nature. _Howitzers_; one-fourth the number of mortars. _Stone Mortars_; one-tenth the number of guns. _Shells_; 400 for each of the 10 and 13 inch mortars, and 600 for each of the smaller ones. _Beds_ for mortars; one-third to spare. _Carriages_ for howitzers; one-third to spare. _Hand Grenades_; 4 or 5000 for the two first classes; 2000 in the three following classes; and from 1500 to 600 in the three last classes. _Rampart Grenades_; 2000 for the first class; 1000 for the four following classes; and 500 for the sixth class; none for the two last. _Fuzes_; one-fourth more than the number of shells. _Bottoms_ of wood for stone mortars; 400 per mortar. _Sand Bags_; 500 for every piece of ordnance in the large places, and one-fourth less in the small ones. _Handspikes_; 10 per piece. _Tackle Falls_ for gins; 1 for every 10 pieces to spare. _Musquets_; 1 per soldier, and the same number to spare. _Pistols_, pairs; one half the number of musquets. _Flints_; 50 per musquet, and 10 per pistol. _Lead_ or _Balls_ for small arms; 30 pounds per musquet. _Powder for small arms_; 5 pounds for every musquet in the garrison, including the spare ones. The above proportions are taken from Durtubie’s Manuel De l’Artilleur. The following method of regulating the management of the artillery, and estimating the probable expenditure of ammunition in the defence of a fortified place, is extracted from a valuable work on fortification lately published at Berlin. It is particularly applied to a regular hexagon: the siege is divided into three periods, viz. 1st. From the first investiture to the first opening of the trenches, about 5 days. 2d. From the opening of the trenches to the effecting a lodgement on the glacis, about 18 days. 3d. From this time to the capitulation, about 5 days. _First Period._ Three guns on the barbette of each bastion and on the barbettes of the ravelins in front of the gate ways, half 24 prs. and half 18 prs.[4] three 9 prs. on the barbette of each of the other ravelins. [4] For 16 prs. in the French work, we have said 18 prs....for 8 prs. 9 prs....for 12 inch mortars, 13 inch: to which they nearly answer, our measures being generally the same as the English. Twelve 12 prs. and twelve 4 prs. in reserve. One 13 inch mortar in each bastion. Six of 8 inch in the salient angles of the covert way.