The boxes are suspended by chains and hooks, and those slung across the bowsprit and outriggers, are fixed by staples. The two inner ones are laid with leaders of quick match, which fire instantly, or with portfires, which burn a given time; they communicate with the outer ones by reeds, which are tied down on the bowsprit and outriggers. The boxes hanging from the deadeyes and shrouds, are fired by curtains suspended from the shrouds, the lower one of which hangs immediately over one of the large fire barrels. The two boxes on each yardarm are hung one over the other; the upper one having a leader of quick match carried along the yard from the shrouds; and in burning will no doubt fire the lower one. Besides the boxes, there are fire barrels arranged as follows; 2 half barrels on the forecastle; 2 abaft the main deck, and 4 on the main deck; 2 in each roundtop, placed against the masts; and 4 large fire barrels under fire trunks, to convey fire to the curtains on the shrouds. All these fire barrels and boxes are to be fired by separate leaders of quick match or portfire, in order that any part of the ship may be fired to cover its approach by the smoke; and the remaining part instantaneously upon quitting the ship. It has been found by experiment, that two men with lighted portfires can set fire to the whole of the leaders on the deck, bowsprit, catheads, outriggers, &c. in less than a minute; therefore the risk of trusting to one main leader to the whole, may be avoided. The leaders are laid in painted canvass hose made for the purpose. _FLINTS_—are usually packed in half barrels. Weight. Qrs. lbs. {Musquet, 2000 2 14 One half barrel contains {Carbine, 3000 2 10 {Pistol, 4000 2 15 The most transparent and free from veins are esteemed the best flints. cwts. qrs. 28 kegs of musquet flints take 18 0 in tonnage 10 kegs of pistol ” ” 3 2 ” _FORTIFICATION.—Practical Maxims in building Field Works._ 1st. The spot on which works are to be constructed should determine their figure; nor should any attention be paid to preserve a regular form which does not occupy the ground to advantage. 2d. Every line must be so disposed, that the slope of hills all around even to the very bottom, be open to the small arms of the garrison; and every part should be discoverable to the distance of at least 500 paces. 3d. Works thrown up for the defence of a defile, should always be within musquet shot of it, which must not be more than 200 yards. 4th. The best defence in works that are flanked, or where one side is defended by the fire of another, is that formed by right angles. 5th. A salient angle should never be less than 60, and a re-entering angle than 90 degrees; nor greater than 120 degrees.