RECKONING
, in Navigation, is the estimating the quantity of a ship's way; or of the course and distance run. Or, more generally, a ship's Reckoning is that account, by which it may at any time be known where the ship is, and consequently on what course or courses she must steer to gain her intended port. The Reckoning is usually performed by keeping an account of the courses steered, and the distance run, with any accidental circumstances that occur. The courses steered are observed by the compass; and the distances run are estimated from the rate of running, and the time run upon each course. The rate of running is measured by the log, from time to time; which however is liable to great irregularities. Anciently Vitruvius, for measuring the rate of sailing, advised an axis to be passed through the sides of the ship, with two large heads protending out of the ship, including wheels touching the water, by the revolution of which the space passed over in a given time is measured. And the same has been since recommended by Snellius.
Reckoning, Dead. See Dead Reckoning.
RECLINATION of a Plane, in Dialling, is the angular quantity which a dial-plane leans backwards, from an exactly upright or vertical plane, or from the zenith.
