APHRACTI. Ancient vessels with open waists, resembling the present Torbay-boats.
APLANATIC. That refraction which entirely corrects the aberration and colour of the rays of light.
APLETS. Nets for the herring-fishery.
APLUSTRE. A word applied in ancient vessels both to the ornament on the prow and to the streamer or ensign on the stern. Here, as in the rudder-head of Dutch vessels frequently, the dog-vane was carried to denote the direction of the wind.
APOBATHRÆ. Ancient gang-boards from the ship to the quays.
APOCATASTASIS. The time in which a planet returns to the same point of the zodiac whence it departed.
APOGEE. That point of the moon's orbit which is furthest from the earth; the opposite of perigee. The apogee of the sun is synonymous with the aphelion of the earth. The word is also used as a general term to express the greatest distance of any heavenly body from the earth.
A-POISE. Said of a vessel properly trimmed.
APOSTLES. The knight-heads or bollard timbers, where hawsers or heavy ropes are belayed.
APOTOME. The difference of two incommensurable mathematical quantities.