DECIUS Mus, a celebrated Roman consul, who, after many glorious exploits, devoted himself to the gods' names for the safety of his country in a battle against the Latins, about 340 years before the Augustan age. His son Decius imitated his example, and devoted himself in like manner in his fourth consulship, when fighting against the Gauls and Samnites. His grandson also did the same in the war against Pyrrhus and the Tarentines. This action of devoting oneself was of infinite service to the state. The soldiers were animated by the example, and induced to follow with intrepidity a commander who, arrayed in an unusual dress, and addressing himself to the gods with solemn invocation, rushed into the thickest part of the enemy to meet his fate.

Decius (Cn. Metius, Q. Trajanus), a native of Pannonia, sent by the emperor Philip to appease a sedition in Moesia. Instead of obeying his master's command, he assumed the imperial purple, and soon after marched against him, and at his death became the only emperor. He signalized himself against the Persians; and when he marched against the Goths, he pushed his horse into a deep marsh, from which he could not extricate himself, and he perished with all his army by the darts of the barbarians, A.D. 251, after a reign of two years.

DECK OF A SHIP, (from decken, Dan. to cover); the planked floors of a ship, which connect the sides together, and serve as different platforms to support the artillery and lodge the men, as also to preserve the cargo from the sea in merchant-vessels. As all ships are broader at the lower deck than on the next above it, and as the cannon thereof are always heaviest, it is necessary that the frame of it should be much stronger than that of the others; and for the same reason the second or middle deck ought to be stronger than the upper deck or forecastle.

Ships of the first and second rates are furnished with three whole decks, reaching from the stem to the stern, besides a forecastle and a quarter-deck, which extends from the stern to the mainmast; between which and the forecastle a vacancy is left in the middle, opening to the upper deck, and forming what is called the waist. There is yet another deck above the hinder or aftmost part of the quarter-deck, called the poop, which also serves as a roof for the captain's cabin or couch.

The inferior ships of the line of battle are equipped with two decks and a half; and frigates, sloops, &c., with one gun-deck and a half, with a spar-deck below to lodge the crew.

The decks are formed and sustained by the beams, the clamps, the water-ways, the carlings, the ledges, the knees, and two rows of small pillars called flanchions, &c. See those articles.

That the figure of a deck, together with its corresponding parts, may be more clearly understood, we have exhibited a plan of the lower-deck of a 74 gun ship in Plate CLVI. And as both sides of the deck are exactly similar, the pieces by which it is supported appear on one side, and on the other side the planks of the floor of which it is composed, as laid up on those upper pieces.

A, the principal or main hatch-way. B, the stern-post. C, the stem. D, the beams, composed of three pieces, as exhibited by D, in one of which the dotted lines show the arrangement of one of the beams under the other side of the deck. E, part of the vertical or hanging knees. F, the horizontal or lodging knees, which fasten the beams to the sides. G, the carlings ranging fore and aft, from one beam to another. H, the gun-ports. I, the pump-dales, being large wooden tubes, which return the water from the pumps into the sea. K, the spurs of the beams, being curved pieces of timber serving as half-beams to support the decks, where a whole beam cannot be placed on account of the hatchways. L, the wing-transom, which is bolted by the middle to the stern-post, and whose ends rest upon the fashion-pieces. M, the bulk-head or partition, which incloses the manger, and prevents the water which enters at the hawse-holes from running aft between decks. NN, the fore hatch-way. OO, the after hatch-way. PP, the drum-head of the gear capstern. PP, the drum-head of the main capstern. QQ, The wing-transom knee. RR, one of the breast-hooks under the gun deck. SS, the breast-hook of the gun-deck. TT, the station of the chain-pumps. VV, the breadth and thickness of the timbers at the height of the gun-deck. UU, sentinels leading to the gunner's store-room, and the bread-room. WW, the station of the fore-mast. XX, the station of the main-mast. YY, the station of the mizen-mast. ZZ, the ring-bolts of the decks, used to retain the cannon whilst charging. aa, The ring-bolts of the sides whereon the tackles are hooked that secure the cannon at sea. cc, The waterways, through which the scupper holes are pierced, to carry the water off from the deck into the sea. bb, Plan of the foremost and aftmost cable-bits, with their cross-pieces gg, and their standards ee.

Thus we have represented on one side all the pieces which sustain the deck with its cannon; and on the other side, the deck itself, with a tier of 32 pounders planted in battery thereon. In order also to show the use of the breeching and train-tackle, one of the guns is drawn in as ready for charging.

The number of beams by which the decks of ships are supported, is often very different, according to the practice of different countries; the strength of the timber of which the beams are framed; and the services for which the ship is calculated.

As the deck which contains the train of a fire-ship is furnished with an equipage peculiar to itself, the whole apparatus is particularly described in the article Fire-ship.

Flysh-Deck implies a continued floor laid from stem to stern, upon one line, without any flops or intervals.

Half-Deck, a space under the quarter deck of a ship of war, contained between the foremost bulk-head of the steerage and the fore-part of the quarter-deck. In the colliers of Northumberland the steerage itself is called the half-deck, and is usually the habitation of the crew.