LOFTUS, WILLIAM KENNETT (c.1821-58). An English arehceologist, born at Rye in Sussex. He was educated at Cambridge, and from l849 to 1852 made extensive on the sites of the ancient cities on the Tigris and Euphrates. In 1853-55, under the auspices of the Assyrian Excavation Fund, he made particular examina tion of Nineveh and Babylon, returning with highly valued collections for the British Museum. He published Tra-vas and Researches in Chaldcea and Susiana (1857) ; and contributed to Quarterly Journal of the Geological Society and to the Journal of the Royal Geographical Society.
LOG (Saved. logy, Dan. log, ship's log: ulti mately connected with Eng. log, felled tree, and with Teel. liygjo, AS. !legal?, Eng. lie). An ap paratus for ascertaining the speed of a ship through the water. Logs are of two kinds, the old-type chip Joy and the patent or taffrail The former consists of the log-chip, log-line, reel, and time-glass (14-second or 28-second). The chip consists of a piece of board about half an inch thick and cut in the shape of a quadrant of a circle of about six inches radius. Along its curved edge there is a groove filled with lead to ballast it and assist to keep it vertical, and near each angle there is a hole. In the holes at the ends of the circular arc are passed the ends of a small piece of rope which are knotted on the other side to keep them from pulling through. In the middle of this piece of rope is seized a wooden plug called a toggle. The end of the log-line is passed through the other hole in the chip and similarly knotted; on the log-line there is secured a piece of wood with a hole or socket in it for the toggle, and its distance from the ehip is such that when the toggle is inserted the three lines hold the chip horizontal if the log-line is held vertically. The log-line consists of a small rope (untarred hemp usually) about one-quarter of an inch in diameter and 150 fathoms long, and is wound upon a reel fitted to turn easily upon its axis, which protrudes beyond the reel to form handles by which it is held.
The log-line is marked as follows: For a certain distance from the chip, usually about 20 fathoms, there are no marks; this is called the stray-line and must he long enough to let the chip get well clear of the eddies at the stern of the ship. The end of the stray-line is marked
with a white rag. From that measure off the length for one knot (about 47 feet 3 inches for a 28-second glass) and mark it with a piece of cord worked into the lay of the rope and having one knot tied in its end; the second knot is marked with a similar piece of cord (usually hard-twisted fish-line) having two knots on it, and so on. Each knot is subdivided and marked at every two-tenths with a small piece of cord without knots.
The time-glasses are shaped like the conven tional hour-glass and filled with a black sand which should he kept dry and free-running. To heave the log requires at least two pref erably three or more if the ship is going over four knots. One man holds the reel and another the glass; after throwing the log-chip (the toggle pressed firmly into the socket) over the stern he waits for the white rag at the end of the stray line to pass over the ship's rail; if the reel does not work easily he assists it by pulling on the line, for no strain must come on the chip, nor must the line lie slack in.the water. When the white rag crosses the rail he turns the glass quickly or directs another man to (10 so—if there is a third—and when the sand is out the person holding the glass calls 'Up." The line is grasped and held and the number of knots and tenths which have run out is noted. The pressure of the water against the chip when the line is held causes the toggle to pull out of the socket ; the chip then lies flat on the water and the line is easily drawn in. When the line is properly marked, the glass in good order, and the heaving of the log carefully done, the result should not be in error more than two-tenths of a knot and should average less. But it must he remembered that this method only determines the speed at a particular moment, and this may not he the average speed during the interval for which the speed is desired.