LENS 456 LENTIL member of the Wisconsin House of Rep- resentatives and served as its speaker in 1903 and 1905. He was elected to the 61st Congress in 1909 and was succes- sively re-elected until his election to the Senate in 1918. He took a prominent part in the Senate debates on the Treaty of Peace and the League of Nations. He was one of the most prominent of the Republican Senators who advocated the so-called mild reservations. He was gen- erallv recognized as one of the most able members of the Senate. LENS, a town of France, in the Pas- de-Calais department, 9 miles N. W. of Arras. Has coal mines and sugar refin- eries. Is well fortified. In their great race to the sea in 1914 the Germans cap- tured Lens and threatened to outflank the French army, so that most of the French forces were compelled to retire to the hills in the vicinity. The German lines were then formed in a prominent salient westward embracing Ablain-St. Nazaire and Carency on the higher ground so as to insure possession of Lens which was an important center of communications. Here the German trench works were elaborate, including such work as the famous Labyrinth. Nevertheless the works were taken by the French in June, 1915, and remained in their hands till the German spring drive of 1918. Pop. about 25,000. LENS, a transparent substance, usu- ally glass, surrounded by curved surfaces so formed that rays of light passing through it are made to change their di- rection, and to magnify or diminish ob- jects at a certain distance. Lenses are double convex, or convex on both sides; double concave, or concave on both sides; piano convex, or piano concave, i. e. with one side plane and the other con- vex, or concave, or convex on one side and concave on the other. If the con- vexity be greater than the concavity, or if the two surfaces would meet if pro- duced, the lens is called a meniscus; and if the concavity be greater than the con- vexity, the lens is termed concavo-con- vex. Every system of lenses, however complicated and whatever be the mutual distances of the lenses, will, if the whole be centered on a common axis, produce a real image somewhere in front of the last refracting surface, or else will ap- pear to produce a virtual image some- where behind. The rays on being traced through the complex combination — e. g., a telescope — undergo numerous devia- tions: ultimately there is a deviation which might have been equally produced by an equivalent lens; equivalent in the sense of producing an equal ultimate de- viation, for the image is not formed in the same place as the "single equivalent lens" would have formed it in. The sys- tem of lenses is approximately equiva- lent in its action to a simple lens plus a determinate shifting of the focus. Hence a simple lens-diagram, modified so as to represent the shifting, will rep- resent the aggregate effect of the most complex system of lenses. See Observ- atory. LENT, a holy season of the Church, of long observance in some communions. Roman Church. — A fast — formerly of varying duration, but now of 40 days — observed as a preparation for the Easter festival. The severity of the Lenten fast is now much modified, and the extent (both as to time and quantity) to which lacticinia may be used is made known by the Lenten indults published by the bishops, and read in all the churches of the diocese at the parochial mass. Greek Church. — The Greek Lent lasts for seven weeks — 35 days, for on all Sat- urdays (except Holy Saturday), on the Feast of the Annunciation, and on all Sundays, the law of fasting is not in force. Strict abstinence from flesh- meat and lacticinia begins on the Mon- day in Quinquagesima week. Anglican Chiirch. — In the "Table of Days of Fasting and Abstinence," the Forty Days of Lent stand first ; but from the Reformation till about the middle of the 19th century the practice of fasting gradually fell into desuetude. With the Oxford movement came an endeavor to restore ancient practices and discipline; and the influence of the High Church clergy has been productive of a stricter observance of this penitential season throughout the Church. LENTIL, a small branching plant, about a foot and a half high; the leaves with 8 to 12 oblong leaflets, and pale blue flowers in twos and threes, and short legumes with two to four seeds. In Egypt and Syria lentils, parched in a frying-pan, are sold as nourishing food, especially for those who are going on long journeys. In France and Germany three varieties are cultivated, the small brown, which is the lightest flavored and the best for haricots and soups; the yellow- ish one, which is a little larger and the next best, and the lentil of Provence, nearly as large as a pea, with luxuriant straw, and more suited for fodder than for human food. From the seeds of len- tils is prepared Revalenta arabica. The lentils of Scripture were Ervurn lens, the red pottage made by Jacob was com- posed of them (Gen. xxv. 34; II Sam. xviii: 11; Ezek. iv: 9).
