Buoy
2 of the 7 encyclopedias on this shelf carry an entry for Buoy. Both are reproduced below, so you can see where they agree and where they differ.
Aiton's Encyclopedia (1910)
boi, in navigation, any float designed to indicate a rock, shallow, or channel. A row of buoys may be anchored along either side of a channel leading amid rocks or shallows to a harbor, in which case those of one series are painted usually of a color strongly contrasting with that of the other series. A pilot is assisted by knowing that he must steer, for instance, to the right of all red buoys and to the left of all black ones. When proceeding up stream or toward the head of a harbor or estuary, the pilot leaves flat-topped buoys on the port hand and conical-shaped buoys on the starboard hand. Spherical buoys indicate a shallow with a channel on each side. Bell buoys carry a bell rung by the heaving of the waves. Lamps and even electric lights, in a shore circuit, of course, are employed to render buoys visible at night. A life buoy is a life preserver , made usually of first crop cork covered with painted canvas. It is made in the form of a belt and is designed to surround the body below the armpits, and keep a person afloat till boats can reach him. Ships are required by law to carry life buoys accessible in case of disaster. 2026 Editor's Note: Buoyage was finally standardized worldwide — but with a catch that still catches sailors out. Under the IALA system agreed in 1980, the world is split into two regions: in the Americas, Japan and Korea red buoys are kept to starboard when entering harbor ("red right returning"); almost everywhere else the colors are reversed. Modern buoys also carry weather instruments and satellite transmitters. (Ed: BR 2026-06-17)
Collier's New Encyclopedia (1921)
any floating body employed to point out the particular situation of a ship's anchor, a shoal, the direction of a navigable channel, etc. They are made of wood, or, now, more commonly of metal. They are generally moored by chains to the bed of the channel, etc. They are of various shapes, and receive corresponding names; thus, there are the can buoy, the nun buoy, the bell buoy, the m mooring buoy, the whistling buoy, etc. The name is also given to a floating object intended to keep a person afloat till he can be taken from the water: more particularly called a life buoy.