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The lock was early used by the Egyptians. Locks and keys of brass and iron have been found in the ruins of Pompeii and Hercula-neum. Mechanical genius has taxed itself to make a lock that cannot be picked. During the London exhibition of 1851 a prize of 200 guineas was offered to anyone who could pick the Bramah lock. Hobbs, an American, won the prize; but he spent 14 days in inventing and making his tools and, afterward, 51 hours in picking the lock. Combination-locks are used for burglar-proof safes. These locks can be opened only by certain movefnents of the handle on an index. Yale of Philadelphia invented an improvement by which the lock can be opened only at a certain time, even by those who know the combination, a timepiece being set with the lock. Changeable keylocks can be locked by any one of a number of keys, but opened only by the one locking it. Some of the locks will give a choice from 60,000,000 keys. See Treatise on Construction of Locks by Hobbs and Tomlinson.
Lock on a river or canal is a double set of gates with a walled-in passage between, by which a boat can pass from one part of a canal or river to another of a different level. The first gate is opened and the boat enters the lock or passage, then the lower gate is closed and the upper one opened, when the water rushing in soon raises the boat to the desired level. The process is reversed when the boat is to be lowered. No canals could be built, except in level countries, without locks.
Locke, John, a great English philosopher, was born on Aug. 29, 1632. He was educated at Oxford, where he became a college-tutor. He studied medicine and practiced at Oxford, but his love of philosophy urged him to other pursuits. In 1670-1 Locke suggested to friends that they ought to discuss What questions is the human understanding fitted or not fitted to deal with? He gave his best talents for 17 years to the subject, and the world received his Essay concerning the Human Understanding. In France he studied and enjoyed the friendship of physicians and naturalists rather than of philosophers. He also spent 1683-88 in study in Holland, returning to England after the Revolution. His first appearance as a writer was The Letter on Toleration (1685), written to a Dutch friend and afterward, translated into English, which involved him in a controversy in the course of which he wrote three other letters on the same subject. In 1690 appeared his Civil Government, a defense of individual liberty, followed by The Human Understanding. This was his first acknowledged work, the others having been published anonymously; and, being translated into Latin and French, it soon spread over Europe. He died on Oct. 28, 1704. See Cousin's Lectures on Locke and Lives by Bourne and Fowler.
Lock'port, a city of New York, county-seat of Niagara County, on the Erie Canal, 25 miles northeast of Buffalo. It is named from the ten double locks by which the canal, here cut through solid limestone, falls 66 feet. This gives a water-power, and the city has abundant electric power, too, making it an important manufacturing point. Chief among its industries are the manufacture of glass, cotton-batting, flour, brooms, carriages and wagons, cotton and woolen goods, aluminum, brass bedsteads, paper and wood-fibre products. Near the city are quarries of fine limestone and sand' stone flagging. Lockport has several churches and an admirable system of public schools. Population 17,970.
Lo'como'tive. See STEAM-ENGINE. Lo'cust. On account of a widespread error in the use of the name, it is difficult to
convince the generality of people that the locust is only a plain grasshopper. Such is the case, however. The so-called 17-year locust is a cicada. The grasshoppers fall into two groups: those with long and those with short antennae. The locusts belong to the former. The locusts mentioned in history are grasshoppers. At times locusts appear in great numbers in oriental countries. A column of flying locusts has been seen in India, estimated to be several hundred miles long and dense enough in some places to obscure the light of the sun. Our Rocky Mountain locust, which has produced so much damage to crops west of the Mississippi, is a small grasshopper very similar to the common red-thighed grasshopper of the eastern United States. The nonmigratory ones, though more easily controlled, work great damage. The California devastating locust and the pellucid locust have been very destructive in California. To the south belongs our largest locust, which is sometimes very destructive. The differential locust has proven a great pest in Mississippi and Louisiana, appearing in countless numbers following an overflow of the Mississippi River succeeded by a dry summer. Eggs are deposited generally from August 10 to September 15, not hatched until the next May, and the insect is full-grown by the last week in June. The destruction of locusts' eggs is of prime importance, and is accomplished by deep fall-plowing or harrowing. Burning dry grass and stubble to destroy newly hatched locusts has proved successful; crushing and ditching are recommended. "Hopper-dozers" containing crude kerosene or coal-tar are used for catching the young in infested fields. Experiments have been made with spreading a fungous disease that attacks
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