Lines of Force — Lion, p. 1077
themselves, but exported large quantities. The cultivation of flax was considerable in Italy just before the Christian era; and it is probable that it was first introduced into England by the Romans. The year 1787 marks the first introduction of a mill for spinning linen-yarn by machinery in the United Kingdom; and it was not until 1812 that the first mill which had any real success was built in London. It is doubtful, however, whether the linen now manufactured is superior to that of the ancient Egyptians, as some of the mummy-cloths in the British Museum contain more than 200 threads to the inch in the warp and over 100 in the woof. The countries in which the manufacture of linen is most extensive are Great Britain, Belgium and France. A large mill was built for the purpose at Fall River, Mass., in 1834; but the industry has not become an extensive one, as most of our linen goods are imported from other countries.
Lines of Force, a term introduced by Faraday, to describe an electric or magnetic field of force. The region about an electric charge or a magnet is such that one has to do work to move another electric charge or a magnet pole respectively. Such a region is called a field of force. This field of force will be completely described when, at every point in the region, the direction and amount of the force on unit charge is given. Faraday accomplishes this description by imagining the region filled with lines such that at every point they have a direction the same as that of the force, and are drawn so thickly (i. e., so close together), that the number of lines passing through unit area, perpendicular to the direction of the force at any point, is numerically equal to the amount of the force. Lines drawn in this manner are called lines of force. In a magnetic field lines of force may be defined in direction by saying that they are lines such that at every point they have a direction the same as that which a freely-suspended compass-needle would assume at that point. Faraday showed that lines of force, whether lines of electric force or lines of magnetic force, behave as if there were a tension along the lines of force and a repulsion between them. The introduction of lines of force has simplified many problems in electricity and magnetism, notably the theory of induced currents. See ELECTRICITY and MAGNETISM.
Linnæus (lǐn-nē'ŭs), Carl, a distinguished botanist, was born in Sweden, May 13, 1707. Almost as soon as he could talk, he knew the names of the plants in his father's garden and of those of the neighborhood. In 1730 he was appointed assistant to the professor of botany at Upsala. His first work was an account of the botanical results of an extended trip through Swedish Lapland. While arranging the gardens and greenhouses of a Dutch banker in Amsterdam he went to England at his patron's expense, and published some of his most famous works, including his Natural System and the Genera of Plants, in which he introduces his system for arranging plants in classes, which, though based on an artificial distinction, was in use for many years. While Linnæus taught botany in the university, his fame and his lectures increased the students from 500 to 1,500, He published several other botanical works and sketches of his scientific excursions. He died at Upsala, Sweden, Jan. 10, 1778. The Linnæan Society of London now owns his books, manuscripts and botanical collection. See Through the Fields with Linnæus by Caddy.
Lin'otype, a machine sometimes known as the Mergenthaler, is employed to cast solid lines out of the type which has been set up. This invention is now universally employed by newspapers and in not a few books. The machine was invented in 1884 by Ottmar Mergenthaler. The solid metal bar, with raised letters, which is made by the linotype, is simply melted down when done with, so that a great expenditure of time and labor in "distributing" the type is entirely avoided.
Lin'seed Oil, the oil made of seed of flax. The seed is first bruised, then ground, and afterward with powerful machinery the oil is pressed out. Sometimes the crushed mass is steamed before the pressure is applied, but the cold-pressed oil is regarded as the better oil, as it is less liable to become rancid than the steam-pressed. The oil is chiefly used in the manufacture of varnishes and paints. The oil-cake,—seed ground after the oil has been pressed out,—is good for poultry and cattle.
Li'on, a very large member of the cat family, inhabiting Africa and southern Asia. The copious mane of long, shaggy hair surrounding the head and neck of the male gives it an appearance of great size. Nevertheless, the lion is exceeded in size and weight by the largest tigers. A full-grown male is about nine and one half or ten feet long without the tail, while the Royal tiger may reach a length of 11 feet. Lions vary in color and in the size of the mane. As a rule, they are tawny or yellowish brown, with the mane darker, but the lioness is not provided with a mane. The tail is long and has a tuft of black hair at the end. Lions are very hard to distinguish by sight, the tawny mane being so like the tall yellow grasses they hide amongst. They live on the plains, rather than in the forests, finding concealment in dense
(Picture) HEAD OP GAMBIAN LION
