Lent (Eries Is well fortified)

Collier's New Encyclopedia (1921)

& eries. Is well fortified. In their ong observ Roman C race to the sea in 1914 the Germans tured Lens and threatened to outflank arying dur the French army, so that most of eserved as French forces were compelled to retire stival. TH the hills in the vicinity. The German now muc lines were then formed in a prominent oth as to t salient westward embracing Ablain eticinia ma Nazaire and Carency on the higher Lenton ground so as to insure possession hops, and Lens which was an important center diocese at communications. Here the German reek Chu trench works were elaborate, including seven wee such work as the famous Labyrinth sys (excep Nevertheless the works were taken st of the the French in June, 1915, and remained days, the in their hands till the German spring e. Strict drive of 1918. Pop. about 25,000. and lacti in Quinqua LENS, a transparent substance, glican Ch ally glass, surrounded by curved surfaces of Fast so formed that rays of light passing Days of I through it are made to change their eformation rection, and to magnify or diminish 9th century jects at a certain distance. Lenses ally fell in double convex, or convex on both sides d movemer double concave, or concave on both sides ancient plano convex, or plano concave, e influenc with one side plane and the other has been vex, or concave, or convex on one ance of t and concave on the other. If the hout the Ch vexity be greater than the concavity, if the two surfaces would meet if duced, the lens is called a meniscus; foot and if the concavity be greater than the 12 oblong vexity, the lens is termed concavo in twos a Every system of lenses, however vex. with two complicated and whatever be the mutual nd Syris distances of the lenses, will, if the whole an, are sol be centered on a common axis, produce for those real image somewhere in front of In Franc last refracting surface, or else will are cultival pear to produce a virtual image somethe lighte where behind. The rays on being traced aricots an through the complex combination - e.g hich is a a telescope-undergo numerous deviaand the tions: ultimately there is a deviation Farge as a which might have been equally produced more surve by an equivalent lens; equivalent in food. Fro sense of producing an equal ultimate ared Revu eripture we made by em (Gen. zek. iv: 97 is not formed in he "single equivalent viation, for the image is not formed in Repned it in. The systhe same place as the "single equivalent in oproximately equiva lens" would have formed it in. The systhe simple lens plus a tem of lenses is approximately equivang of the focus. the lent in its action to a simple lens plus a ns-diagram, modified determinate shifting of the focus. the shifting, will rep- Treaty Hence a simple lens-diagram, modified te effect of the most He so as to represent the shifting, will replenses. See OBSERVthe resent the aggregate effect of the most the complex system of lenses. See OBSERVgenson of the Church, of ATORY. able ome communions.