E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
An instrument for measuring the velocity of a ship. It is a flat piece of wood, some six inches in radius, and in the shape of a quadrant. A piece of lead is nailed to the rim to make the log float perpendicularly. To this log a line is fastened, called the log-line (q.v.). Other forms are also used.
A king Log. A roi fainéant. In allusion to the fable of the frogs asking for a king. Jupiter first threw them down a log of wood, but they grumbled at so spiritless a king. He then sent them a stork, which devoured them eagerly.