2. To move to and fro; to rock. [Obs.]
2. [Prob. the same word as in sense 1; cf. LG. log, lock,
Dan. log, Sw. logg.] (Naut.) An apparatus for measuring
the rate of a ship's motion through the water.
Note: The common log consists of the log-chip, or logship,
often exclusively called the log, and the log line, the
former being commonly a thin wooden quadrant of five or
six inches radius, loaded with lead on the arc to make
it float with the point up. It is attached to the log
line by cords from each corner. This line is divided
into equal spaces, called knots, each bearing the same
proportion to a mile that half a minute does to an
hour. The line is wound on a reel which is so held as
to let it run off freely. When the log is thrown, the
log-chip is kept by the water from being drawn forward,
and the speed of the ship is shown by the number of
knots run out in half a minute. There are improved
logs, consisting of a piece of mechanism which, being
towed astern, shows the distance actually gone through
by the ship, by means of the revolutions of a fly,
which are registered on a dial plate.
3. Hence: The record of the rate of ship's speed or of her
daily progress; also, the full nautical record of a ship's
cruise or voyage; a log slate; a log book.
4. A record and tabulated statement of the work done by an
engine, as of a steamship, of the coal consumed, and of
other items relating to the performance of machinery
during a given time.
5. (Mining) A weight or block near the free end of a hoisting
rope to prevent it from being drawn through the sheave.
{Log board} (Naut.), a board consisting of two parts shutting
together like a book, with columns in which are entered
the direction of the wind, course of the ship, etc.,
during each hour of the day and night. These entries are
transferred to the log book. A folding slate is now used
instead.
{Log book}, or {Logbook} (Naut.), a book in which is entered
the daily progress of a ship at sea, as indicated by the
log, with notes on the weather and incidents of the
voyage; the contents of the log board.
{Log cabin}, {Log house}, a cabin or house made of logs.
{Log canoe}, a canoe made by shaping and hollowing out a
single log.