LOFTUS, LORD Augustus William Fred erick Spencer, English diplomatist: b. 4 Oct. 1817; d. 9 March 1904. He entered the diplo matic service in 1837 as attache at Berlin and was likewise attache at Stuttgart in 1844. He was secretary to Stratford Canning in 1848, and after serving as secretary of legation at Stuttgart (1852), and Berlin (1853), was en voy at Vienna (1858), Berlin (1860) and Munich (1862) •, became Ambassador at Berlin 1865, to the North German Confederation (1868-71) and to Saint Petersburg (1871-79). He was governor of New South Wales (1879 85). He published his Reminiscences (1892 94).
LOG, in nautical parlance, an apparatus used to measure the rate of a ship's velocity through the water. For this purpose there are several inventions, but the one most generally used is the following, called the common log. It is a piece of thin board, forming the quad rant of a circle of about six inches radius, and balanced by a small plate of lead, nailed on the circular part, so as to float vertically in the water, with the greater part immersed. The log-line is fastened to the to by means of three leads, two being knotted, through holes at one corner and the top while the other is attached to a pin fixed in a hole at the other corner, so as to draw out when a considerable force is exerted on it. The log-line is divided by means of knots of colored cloth into equal lengths, which are in the same proportion to an equal number of geographical or nautical miles, as a half or quarter minute is to an hour of time. It is wound upon a reel. The whole is employed to measure the ship's head-way in the following manner:— The reel being held by one man, and the half-minute glass by another, the mate of the watch fixes the pin and throws the log over the stern, which floating vertically offers immediate resistance through its area set at right angles to the direction of the ship, and is considered as stationary, the line being allowed to run freely over the stern to prevent the pin being pulled out. The knots are measured from a mark on the line at the distance of 12 or 15 fathoms from the log. The part of the line between the log and this mark is called the stray-line. The glass is turned at the instant that the mark passes over the stern, and as soon as the sand in the glass is run out the line is stopped. The resistance of the water then acting on the log dislodges the pin, so that the board, now presenting only its edge to the water, is easily drawn aboard. The number of knots which had run off at the expiration of the glass determines the ship's velocity. Two
types of sand-glasses are in common use among mariners, one emptying in 30 seconds, and the other in 28 seconds. In the first instance, in laying out the knots in a log line the proportion would read: I hour (3,690 sec.): 3o: : r mile (6,o8o feet): r knot.
making the length of the "knot" — that is, the length between two knots on the line — 50 feet 7 inches. Where the 28-second sand glass is used the "knot') is 47 feet 3 inches in length. Where the speed of the vessel is greater than six knots that is, six nautical miles per hour— the line would run out an inconvenient distance in 28 or 30 seconds, so in faster ships a 14 second or 15-second glass is used, and the num ber of knots passing in that period multiplied by two to give the speed per hour.
The patent log or taffrail log is an alto gether different instrument for the same pur pose. Instead of a long line running out freely, the patent log has a fixed length of line, about three fathoms for each knot of the ship's average speed, and is dragged after the ship. The drag is an arrangement similar to a screw, having a central shank, and fins running lengthwise around it in helical form. When it is dragged through the water the fins cause it to rotate, and the faster it is dragged the faster it rotates. The entire log line turns with it and the number of turns is recorded by mechanism fastened to the taffrail of the vessel, and is shown on a dial.
a book in which . are offici cially recorded the proceedings on board a ship, supplied in England by the Board of Trade. In it the contents of the log-board are daily trans scribed at noon, together with every circum stance deserving notice that may happen to the ship or within her cognizance, either at sea or in a harbor, etc. In addition to the weather, speed, astronomical observations, etc., the en tries required to be made include convictions, offenses, punishments, conduct of crew, illnesses and injuries, deaths, births and marriages, quit ting the ship, wages of men entering the navy, wages of deceased seamen, sale of deceased sea men's effects, collisions — in short, every con dition, occurrence and transaction which comes under official notice. The log-book must be signed by master and mate, and certain other persons in particular cases. Properly authenti cated entries are admissible in a court of law. A log is also kept •by the master for the bene fit of the owners. On steamships the chief engineer is also responsible for the keeping of a log in which are recorded all details con nected with his department while the ship is at sea.