David Johnson, age 11, of North Windham, Maine, for his question:

WHAT IS A BINNACLE?

A binnacle is the stand that holds a ship's compass.

A ship's compass is often called a mariner's compass. It is a device for determining directions. It has a number of magnets fastened on a flat disk, called a compass card. This card is marked with the points and degrees of direction. The card rests on a pivot so it can turn freely inside the glass covered compass bowl and can always point toward magnetic north.

The compass bowl is filled with a nonfreezable liquid mixture of alcohol and water or glycerin and water. The liquid floats the card and at the same time slows the movement of the card so that it does not constantly swing from side to side with the motion of the ship.

A black vertical line, called the lubber's line, is marked inside the compass bowl. The compass card point opposite the lubber's line indicates the direction the ship is heading.