APPRAISEMENT. A law instrument taken out by the captors of a vessel, who are primarily answerable for the expense.
APPRENTICE. One who is covenanted to serve another on condition of being instructed in an art, and ships' apprentices are to the same effect. Boys under eighteen years of age bound to masters of merchant ships were exempted from impressment for three years from the date of their indentures; which documents were in duplicate, and exempt from stamp duty.
APPROACHES. The trenches, zig-zags, saps, and other works, by which a besieger makes good his way up to a fortified place. (See [Trenches].)
APPROVAL. The senior officer's signature to a demand or application.
APPROXIMATION. A continual approach to a quantity sought, where there is no possibility of arriving at it exactly.
APPULSE. A near approach of one heavenly body to another, so as to form an apparent contact: the term is principally used with reference to stars or planets when the moon passes close to them without causing occultation.
APRON, or Stomach-piece. A strengthening compass timber fayed abaft the lower part of the stern, and above the foremost end of the keel; that is, from the head down to the fore dead-wood knee, to which it is scarfed. It is sided to receive the fastenings of the fore-hoods or planking of the bow.—Apron of a gun, a square piece of sheet-lead laid over the touch-hole for protecting the vent from damp; also over the gun-lock.—Apron of a dock, the platform rising where the gates are closed, and on which the sill is fastened down.
APSIDES, Line of. The imaginary line joining the aphelion and perihelion points in the orbit of a planet.
APSIS. Either of the two points in planetary orbits where they are at the greatest and the least distance from the sun, and are termed higher or lower accordingly. The two are joined by a diameter called the line of the apsides.
AQUAGE. The old law-term denoting the toll paid for water-carriage.