ARGONAUTS. A company of forty-four heroes who sailed in the _Argo_ to obtain the golden fleece; an expedition which fixes one of the most memorable epochs in history. Also a Geographical Society instituted at Venice, to whom we owe the publication of all the charts, maps, and directories of Coronelli. ARGOSY. A merchant ship or carrack of burden, principally of the Levant; the name is by some derived from Ragusa, but by others with more probability from the _Argo_. Shakspeare mentions "argosies with portly sail." Those of the Frescobaldi were the richest and most adventurous of those times. ARGOZIN, OR ARGNESYN. The person whose office it was to attend to the shackles of the galley-slaves, over whom he had especial charge. ARGUMENT. An astronomical quantity upon which an equation depends,--or any known number by which an unknown one proportional to the first may be found. ARGUMENT OF LATITUDE. The distance of a celestial body from one of the nodes of its orbit, upon which the latitude depends. ARIES. The most important point of departure in astronomy. A northern constellation forming the first of the twelve signs of the zodiac, into which the sun enters about the 20th of March. With Musca, Aries contains 22 nebulæ, 8 double and 148 single stars, but not above 50 are visible to the unassisted eye. The commencement of this sign, called the first point of Aries, is the origin from which the right ascensions of the heavenly bodies are reckoned upon the equator, and their longitudes upon the ecliptic. ARIS. Sharp corner of stones in piers and docks. ARIS PIECES. Those parts of a made mast which are under the hoops. ARITHMETIC. The art of computation by numbers; or that branch which considers their powers and properties. ARK. The sacred and capacious vessel built by Noah for preservation against the flood. It was 300 cubits in length, 50 in breadth, and 30 in height; and of whatever materials it was constructed, it was pitched over or pay'd with bitumen. _Ark_ is also the name of a mare's-tail cloud, or cirrhus, when it forms a streak across the sky. ARLOUP. An archaism for the deck, now called _orlop_ (which see). ARM. A deep and comparatively narrow inlet of the sea. That part of an anchor on which the palm is shut. The extremity of the bibbs which support the trestle-trees. Each extremity or end of a yard, beam, or bracket.--_To arm_, to fit, furnish, and provide for war; to cap and set a loadstone; to apply putty or tallow to the lower end of the lead previous to sounding, in order to draw up a specimen of the bottom.--_To arm a shot_, is to roll rope-yarns about a cross-bar-shot, in order to facilitate ramming it home, and also to prevent the ends catching any accidental inequalities in the bore. ARMADA. A Spanish term signifying a royal fleet; it comes from the same root as army. The word _armado_ is used by Shakspeare.