LOCH LOCKE. 



507 



before casting its shell, the limb becomes contracted 

 to such a degree as to be capable of being withdrawn 

 through the joints and narrow passage near the body. 

 Like all other crustaceous animals, they only increase 

 in size whilst in a soft state. The circumstance of 

 lobsters losing their claws on occasion of thunder- 

 claps, or the sound of cannon, is well authenticated. 

 The restoration of claws lost thus, or from their fre- 

 quent combats with each other, in which the van- 

 quished party generally leaves one of his limbs in his 

 adversary's grasp, may be readily observed, as the 

 new limb seldom, if ever, attains the size of the 

 former. These animals are very sensible to the 

 shock communicated to the fluid in which they live, 

 by the firing of cannon. In the water, they are very 

 rapid in their motions, and, when suddenly alarmed, 

 can spring to a great distance. They attain their 

 retreat in a rock with surprising dexterity, throwing 

 themselves into a passage barely sufficient to permit 

 their bodies to pass. They are extremely prolific : 

 Dr Baster says that he counted 12,444 eggs under 

 the tail of a female lobster, besides those that 

 remained in the body miprotruded. The female 

 deposits these eggs in the sand, where they are soon 

 hatched. 



LOCH ; the Scottish for lake. 



LOCH KATRINE, or CATHARINE; a small 

 lake of Scotland, in the county of Perth, in the 

 Grampian hills, celebrated for the picturesque beau- 

 ties of its shores. It has become famous as the scene 

 of the Lady of the Lake. Bordering on it are the 

 mountains called the Trosachs, full of wildness and 

 rude grandeur. The access to the lake is through a 

 narrow pass, about half a mile in length, " the Tros- 

 achs' rugged jaws." 



LOCH LEVEN. See Leven. 



LOCH LOMOND; a lake of Scotland, lying 

 betwixt Dumbartonshire and Stirlingshire, and nearly 

 equally belonging to both. It is about twenty-three 

 miles in length from north to south, and its greatest 

 breadth is five miles. It contains nearly thirty 

 islands of different sizes. It communicates with the 

 Clyde by a river, which joins the Clyde at Dumbar- 

 ton. (See Leven.) This beautiful lake is surround- 

 ed by hills and mountains, and is celebrated for the 

 grand and picturesque scenery of its shores. Its depth 

 is various, in some parts 100 fathoms. It abounds 

 in trout. 



LOCK ; a well known instrument, used for fasten- 

 ing doors, chests, &c., generally opened by a key. 

 The lock is reckoned the masterpiece in smithery, a 

 great deal of art and delicacy being required in con- 

 triving and varying the wards, springs, bolts, &c., 

 and adjusting them to the places where they are to 

 be used, and to the several occasions of using them. 

 The principle on which all locks depend, is the appli- 

 cation of a lever to an interior bolt, by means of 

 a communication from without ; so that, by means of 

 the latter, the lever acts upon the bolt, and moves it 

 in such a manner as to secure the lid or door from 

 being opened by any pull or push from without. The 

 security of locks, in general, therefore, depends on 

 the number of impediments we can interpose betwixt 

 the lever (the key) and the bolt which secures the 

 door ; and these impediments are well known by the 

 name of wards, the number and intricacy of which 

 are supposed to distinguish a good lock from a bad 

 one. If these wards, however, do not, in an effectual 

 manner, preclude the access of all other instruments 

 besides the proper key, it is still possible for a 

 mechanic, of equal skill \vith the lockmaker, to open 

 it without the key, and thus to elude the labour of 

 the other. Various complicated and difficult locks 

 have been constructed by Messrs Bramah, Taylor, 

 Spears, and others. In a very ingenious lock, in- 



vented by Mr Perkins, twenty-four small blocks of 

 metal, of different sizes, are introduced, corresponding, 

 to the letters of the alphabet. Out of these, an 

 indefinite number of combinations may be made. 

 The person locking the door selects and places the 

 blocks necessary to spell a particular word, known 

 only to himself, and no other person, even if in pos- 

 session of the key, can open the door, without a 

 knowledge of the same word. 



LOCKS. When a canal varies from one level to an- 

 other of different elevation, the place where the change 

 of level takes place, is commanded by a lock. Locks 

 are tight, oblong enclosures, in the bed of the canal, 

 furnished with gates at each end, which separate the 

 higher from the lower parts of the Canal. When a boat 

 passes up the canal, the lower gates are opened, and 

 the boat glides into the lock, after which the lower 

 gates are shut. A sluice, communicating with the 

 upper part of the canal, is then opened, and the lock ra- 

 pidly fills with water, elevating the boat on its surface. 

 When the lock is filled to the highest water level, the 

 upper gates are opened, and the boat, being now on 

 the level of the upper part of the canal, passes on its 

 way. The reverse of this process is performed when 

 the boat is descending the canal. Locks are made of 

 stone or brick, sometimes of wood. The gates are 

 commonly double, resembling folding doors. They 

 meet each other, in most instances, at an obtuse 

 angle, and the pressure of the water serves to keep 

 them firmly in contact. Cast iron gates are some- 

 times used in England, curved in the form of a hori- 

 zontal arch, with their convex side opposed to the 

 water. In China, inclined planes are said to be used 

 instead of Jocks, along which the boats are drawn up 

 or let down. They have also been used in Europe, 

 and on the Morris canal, in New Jersey, America. 



LOCKE, JOHN, one of the most eminent philoso- 

 phers and valuable writers of his age and country 

 was born at Wrington, in Somersetshire, Aug. 29, 

 1632. His father, who had been bred to the law, 

 acted in the capacity of steward, or court-keeper, to 

 colonel Alexander Popham, by whose interest, on the 

 breaking out of the civil war, he became a captain in 

 the service of parliament. The subject of this article 

 was sent, at a proper age, to Westminster school, 

 whence he was elected, in 1651, to Christ church 

 college, Oxford. Here he distinguished himself much 

 by his application and proficiency; and, having taken 

 the degree of B. A. in 1655, and of M. A. in 1658, 

 he applied himself to the study of physic. In the year 

 1664, he accepted an offer to go abroad, in the 

 capacity of secretary to Sir William Swan, envoy 

 from Charles II. to the elector of Brandenburg, and 

 other German princes; but he returned, in the course 

 of a year, and resumed his studies with renewed 

 ardour. In 1666, he was introduced to lord Ashley, 

 afterwards the celebrated earl of Shaftesbury, to 

 whom he became essentially serviceable in his medical 

 capacity, and who formed so high an opinion of his 

 general powers, that he prevailed upon him to take 

 up his residence in his house, and urged him to apply 

 his studies to politics and philosophy. By his acquain- 

 tance with this nobleman, Mr Locke was introduced 

 to the duke of Buckingham, the earl of Halifax, and 

 others of the most eminent persons of their day. In 

 1668, at the request of the earl and countess of 

 Northumberland, he accompanied them in a tour to 

 France, and, on his return, was employed by lord 

 Ashley, then chancellor of the exchequer, in draw- 

 ing up the Fundamental Constitutions of Carolina. 

 He also superintended the education of that noble- 

 man's son. In 1670, he began to form the plan of 

 his Essay on the Human Understanding, and, about 

 tl:e same time, was made a fellow of the royal society. 

 In 1672, lord Ashley, having been created earl of 



