L E N 



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L E P 



Convex lenses possess peculiar advan- 

 tages for concentrating the sun's rays, 

 and for conveying to an immense distance 

 a condensed and parallel beam of light. 

 The most perfect burning lens ever con- 

 structed was executed by Mr. Parker, of 

 Fleet Street, at an expense of 7001. It 

 \tas made of flint-glass, was three feet in 

 diameter, and weighed 212 pounds. By 

 means of this powerful burning lens, 

 platina, gold, silver, copper, tin, quartz, 

 agate, jasper, flint, topaz, garnet, &c., 

 were melted in a few seconds. Brew- 

 ster. 



LENTICE'LL^E. The name given by De 

 Candolle to certain points, which appear 

 as dark spots, on the surface of the bark 

 of plants. 



LENTI'CULAR. (lenticularis, resembling a 

 lentil, Lat. lenticulaire, Fr.) Having 

 the form of a lens. 



In entomology, a round body, with its 

 opposite sides convex, meeting in a sharp 

 edge. In conchology, doubly convex 

 shells. 



LENTI'CULAR ORE. The name given by 

 Jameson to obtuse octahedral arseniate of 

 copper, a variety of arseniate of copper ; 

 called also lenticular arseniate of copper. 



LENTICULI'NA. A sublenticular, multilo- 

 cular, spiral univalve ; a genus of micro- 

 scopic foraminifera. Distinguished from 

 Nautilus by having no syphon. Three 

 species have been found fossil in the 

 neighbourhood of Paris. 



LENTI'CULITE. A fossil shell of a lenticular 

 form. 



LE'NTIFORM. (from lens and/brma, Lat.) 

 Of the form of a lens. 



LB'NZINITE. A mineral found in Germany, 

 and thus named after Lenzius, a German 

 mineralogist. There are two kinds of 

 lenzinite, the opaline and the argillaceous ; 

 the former of a milk-white, the latter of a 

 snow-white colour. 



LE'PADITES. The goose-barnacle. An 

 order of Cirripedes, the species of which 

 are distinguished by a tendinous, con- 

 tractile, and often long tube, fixed by its 

 base to some solid marine substance, 

 supporting a compressed shell, consisting 

 of valves united to each other by mem- 

 brane ; and by having six pairs of tenta- 

 culated arms. They are usually found in 

 places exposed to the fluctuations of the 

 waves. Rev. W. Kirby. 



LE'PAS. (\7rac, Gr. lepas, Lat. lepas, 

 Fr.) Linnaeus included under the name 

 lepas all the cirripedes or multivalves. 

 These animals are known in this country 

 by the name of Barnacles. The lepas, or 

 barnacle, constitutes a connecting link 

 between molluscous and articulated ani- 

 mals ; the gills are attached to the bases 

 of the cirrhi, or jointed tentacula. In 



the Linnsean system, the lepas constitutes 

 the second genus of multivalve shells. 

 The animal a triton ; shell affixed at the 

 base, and consisting of many unequal 

 erect valves. They are without eyes, or 

 any distinct head ; have no powers of 

 locomotion, but are fixed to various bo- 

 dies. Their body, which has no articula- 

 tions, is enveloped in a mantle : their 

 mouth is armed with transverse toothed 

 jaws in pairs, and furnished with a feeler. 

 This genus consists of two families, or 

 divisions, very different in their form, the 

 first of which is the Balanites, or Acorn- 

 barnacles, having a shelly instead of a 

 tendinous tube, with an operculum or lid, 

 consisting generally of four, but some- 

 times of six valves, and being of a sub- 

 conic form. The second family consists 

 of the Lepadites, or Goose-barnacles, the 

 specks of which are distinguished by a 

 tendinous, contractile, and often long 

 tube or pedicle, which, being of a flexible 

 nature, allows the animal, fixed by its 

 base to some solid marine substance, to 

 writhe about in quest of food. The ani- 

 mals of this genus have only been found 

 in the ocean. In Turton's Linne thirty- 

 two species of lepas are described ; fifteen 

 of these have been discovered in our seas. 

 LEPIDODE'NDRON. (from Xeirlg and dsv- 

 dpov, Gr.) An extinct genus of fossil 

 plants, of very frequent occurrence in the 

 coal formation. It is stated by Lindley 

 and Hutton that plants of this genus are, 

 next to the calamites, the most abundant 

 of the fossils in the coal formation of the 

 north of England. Thirty-four species 

 are enumerated by M. Ad. Brongniart. 

 Lepidodendra are sometimes found of 

 enormous size, fragments of stems occur- 

 ring upwards of forty feet in length. 

 Their internal structure has been ascer- 

 tained to be intermediate between coni- 

 ferae and lycopodiacese. In some points 

 of their structure they resemble coniferse, 

 but in other respects, setting aside their 

 great magnitude, they may be compared 

 to lycopodiacese. To botanists, this dis- 

 covery is of very high interest, as it proves 

 that those systematists are right, who 

 contend for the possibility of certain 

 chasms now existing between the grada- 

 tions of organization, being caused by the 

 extinction of genera, or even of whole 

 orders, the existence of which was neces- 

 sary to complete the harmony which it is 

 believed originally existed in the structure 

 of all parts of the vegetable kingdom. 

 By means of Lepidodendron, a better 

 passage is established from flowering to 

 flowerless plants, than by either equise- 

 tum or cycas, or any other known genus. 

 Lindley and Hutton. 



Count Sternberg remarks, that we are 



