LEVEL LEVI. 



453 



Napoleon ordered the levee en-masse, wlien the allies 

 entered France, and it threatened to become dan- 

 gerous to them ; but the capture of Paris put an end 

 to the war. We all know how effectual a levee-en- 

 masse was in Spain, where even women took part 

 in it, and in Tyrol, under Ilofer. We lately wit- 

 nessed a levee-en-masse, in Poland. The French 

 national guard, with its different classes, might be 

 considered a levee-en-masse organized on a gigantic 

 plan. The chief difference between a levee-en-masse 

 and militia is, that, in the former, all persons are 

 comprised not included in the latter ; and they do 

 not march far from home ; and that their service is 

 more irregular, and even owes its strength, in some 

 measure, to this irregularity. 



LEVEL ; a mathematical instrument used for draw- 

 ing a line parallel to the horizon, and continuing it 

 at pleasure, and, by this means, for finding the true 

 level, or the difference of ascent or descent between 

 several places, for conveying water, draining fens, 

 placing the surfaces of floors, &c., level, and for 

 various other purposes in architecture, agriculture, 

 hydraulics, surveying, &c. There is a great variety 

 of instruments for this purpose, differently construct- 

 ed, constituted of different metals, according to the 

 particular purposes to which they are applied ; as 

 the carpenter's level, mason's level, balance level, 

 mercurial levels, surveying and spiral levels ; but, 

 however their construction may vary, they may all be 

 referred to the following three classes : 1. those in 

 which the vertical line is determined by a suspended 

 plumb-line or a balance-weight, and the horizontal 

 position is shown by a line perpendicular to it; 2. 

 those which determine a level line by the surface of a 

 fluid ; 3. spirit levels, which point out the horizontal 

 direction by a bubble of air floating in a fluid con- 

 tained in a glass tube. 1. Those of the first kind, 

 depending upon the plumb-line, are very common, 

 but not very accurate. The simplest form is that of 

 two rulers united in the form of the letter L ; they 

 must be exactly perpendicular to each other ; then, 

 if a plumb-line is suspended from the top of the 

 vertical ruler, and the edge thereof be made to coin- 

 cide with the plumb-line, the other ruler must be 

 horizontal. This, when applied to the top of a wall, 

 a beam, or a floor, will show if they are horizontal. 

 This is the kind of level used by artificers ; some- 

 times it is formed like the letter A, of three rulers, 

 the plumb-line being suspended from the vertex, and 

 the two legs set on the surface to be levelled. The 

 line hangs opposite to a mark made on the middle of 

 the cross ruler, when the feet are on the same level. 

 Sometimes the horizontal piece crosses the perpen- 

 dicular at its foot, and the plumb, suspended from the 

 top of the perpendicular, is received in an opening at 

 their junction. 2. The water level shows the horizon- 

 tal line by means of a surface of water or other fluid, 

 founded on this principle, that water always places 

 itself horizontally. The most simple kind, made of 

 a long wooden trough, which is filled with water, 

 shows on its surface the line of level. This is the 

 ancient chorobates. The water level is also made 

 with two cups fitted to the two ends of a straight 

 pipe, an inch in diameter, and four feet long. The 

 water communicates from one cup to the other ; and 

 this pipe being movable on its stand by a ball and 

 socket, when the two cups are seen to be equally full 

 of water, their two surfaces mark the line of level. 

 This instrument, instead of cups, may also be made 

 with two short cylinders of glass, three or four inches, 

 long, fastened to each extremity of the pipe with 

 wax or mastich. The pipe, filled with coloured 

 water, shows itself through the cylinders, by means 

 of which the line of level is determined ; the height 

 of the water, with respect to the centre of the earth, 



being always the same in both cylinders. This level, 

 though very simple, is yet very commodious for lev- 

 elling small distances. 3. The spirit or air level 

 shows the exact level, by means of a bubble of air, 

 enclosed, with some fluid, in a glass tube of an inde- 

 terminate length and thickness, and having its two 

 ends hermetically sealed. When the bubble fixes 

 itself at a mark in the middle of the tube, the case in 

 which it is fixed is then level. When it is not level, 

 the bubble will rise to one end. This glass tube 

 may be set in another of brass, having an aperture in 

 the middle, where the bubble may be observed. The 

 liquor with which the tubo is filled, is oil of tartar, or 

 aqua secunda, those not being liable to freeze, as 

 common water, nor to rarefaction and condensation, 

 as spirit of wine is. These instances will explain the 

 principle of the different kinds of levels. Their varie- 

 ties are too numerous to be described here. 



LEVEN ; a river which flows from Loch Lomond , 

 and, after a course of about nine miles, falls into the 

 Clyde at Dumbarton. Smollett has celebrated it in 

 a well-known little poem. Printfields and other pub- 

 lic works are now established on its banks. Leven 

 is also the name of a river in Fifeshire, which flows 

 from Loch Leven. 



LEVEN, LOCH ; a lake of Scotland, about ten 

 miles in circumference, in the county of Kinross. It 

 contains four islands, on one of which was formerly a 

 priory, and on another stand the remains of the castle 

 of Loch Leven, once a royal residence, which was 

 granted by Robert III. to Douglas. In this castle 

 Mary Stuart was confined, after her separation from 

 Bothwell, and her capture by the confederate lords, 

 at the battle of Carberry Hill. After several unsuc- 

 cessful attempts, she made her escape, by the aid of 

 George Douglas, her keeper's brother. 



LEVER, in mechanics ; an inflexible right line, 

 rod, or beam, supported, in a single point, on a ful- 

 crum or prop, and used for the raising of weights, 

 being either void of weight of itself, or at least, having 

 such a weight as may be commodiously counterbal- 

 anced. The lever is the first of those called mechani- 

 cal powers, or simple machines, as being, of all others, 

 the most simple ; and is chiefly applied for raising 

 weights to small heights. See Mechanics. 



LEVESQUE, PETER CHARLES ; a French writer on 

 history and general literature, was born at Paris, in 

 1736, and, when young, apprenticed to an engraver. 

 Displaying a strong inclination for learning, he was 

 removed to the college Mazarin, where he studied 

 with great success. His family having retired into 

 the country, he, for some time, supported himself at 

 Paris, by working as an engraver. In 1773, he went 

 to St Petersburg, with a recommendation from Dide- 

 rot to the empress of Russia, who appointed him pro- 

 fessor of belles-lettres at the school of noble cadets. 

 Here he formed the design of writing the history of 

 Russia, and, having completed the work, in 1780 he 

 returned to Paris to publish it. He was admitted 

 into the academy of inscriptions, and, some years 

 after was appointed professor at the royal college. 

 He was subsequently made a member of the national 

 institute; and, in 1812, closed a long life devoted to 

 literary pursuits. Besides his Russian history (4th 

 edition with notes by Malte-Brun and Depping, 

 eight volumes, 1812, a standard work on Russia), he 

 produced a translation of Thucydides; a History of 

 France, under the five first Kings of the House of 

 Valois; a Critical History of the Roman Republic 

 (three volumes); Studies in ancient History, and in 

 the History of Greece, and many other translations 

 and valuable works. 



LEVI ; the third son of Jacob and Leah. The 

 prince of the Sichemites, having ravished his sister 

 Dinah, he, with his brother Simeon, attacked their 



