COMPARTMENT BULK-HEADS. Some of the iron ships have adopted the admirable Chinese plan of dividing the hold athwart-ship by strong water-tight bulk-heads, into compartments, so that a leak in any one of them does not communicate with the others--thus strengthening a vessel, besides adding to its security. Compartment bulk-heads were first directed to be fitted under the superintendence of Commander Belcher in H.M. ships _Erebus_ and _Terror_ at Chatham, for Arctic service in 1835. H.M.S. _Terror_, Commander Back, was saved entirely owing to this fitment, the after section being full of water all the passage home; and lately the mail packet _Samphire_ was similarly saved. COMPASANT. A corruption of _corpo santo_, a ball of electric light observed flickering about the masts, yard-arms, and rigging, during heavy rain, thunder, and lightning. COMPASS. An instrument employed by navigators to guide the ship's course at sea. It consists of a circular box, containing a fly or paper card, which represents the horizon, and is suspended by two concentric rings called gimbals. The fly is divided into thirty-two equal parts, by lines drawn from the centre to the circumference, called points or rhumbs; the interval between the points is subdivided into 360 degrees--consequently, the distance or angle comprehended between any two rhumbs is equal to 11 degrees and 15 minutes. The four cardinal points lie opposite to each other; the north and south points form top and bottom, leaving the east on the right hand, and the west on the left; the names of all the inferior points are compounded of these according to their situation. This card is attached to a magnetic needle, which, carrying the card round with it, points north, excepting for the local annual variation and the deviation caused by the iron in the ship; the angle which the course makes with that meridian is shown by the lubber's point, a dark line inside the box. (_See_ ADJUSTMENT OF THE COMPASS.) COMPASS, TO. To curve; also to obtain one's object. COMPASSING. (_See_ COMPASS-TIMBERS.) COMPASSIONATE ALLOWANCES. Grants are made on the compassionate fund to the legitimate children of deceased officers, on its being shown to the Admiralty that they deserve them. COMPASS-SAW. A narrow saw, which, inserted in a hole bored by a centre-bit, follows out required curves. COMPASS-TIMBERS. Such as are curved, crooked, or arched, for ship-building. COMPENSATION. If a detained vessel is lost by the negligence and misconduct of the prize-master, compensation must be rendered, and the actual captors are responsible. The principal being answerable in law for the agent's acts. COMPENSATOR OF THE COMPASS. _See_ MAGNETIC COMPENSATOR. COMPLAIN, TO. The creaking of masts, or timbers, when over-pressed, without any apparent external defect. One man threatening to complain of another, is saying that he will report misconduct to the officer in charge of the quarter-deck.