EVAPORATION. 809 EVELYN. produced by a rise of 1° in temperature is de- noted by the symbol , tben the heat, of evapora- tion, /, may, according to Clausius, be calculated by Hie following formula:
- =T <ip _(V— V)
the critical temperature (sec Criticai
Point) there is no difference whatever between
- i liquid and its vapor; the difference between the
volumes occupied by one gram of liquid and one gram of vapor is naught, and the heat of evapora- 1 i< hi is likewise naught, as is shown by the above fin inula. Cooling by Evaporation. Since the transfor- mation of liquids into vapors involves the ab- sorption of beat, a liquid may be cooled by allow- ing it to evaporate, while no heat is applied to it : the evaporation will then take place at the ex- pense of the sensible heat of the liquid itself, and as a result, the temperature will be lowered. Thus the rapid evaporation of liquid ammonia or of sulphurous acid produces temperatures low enough for water to freeze, and is employed in making artificial ice. Liquid ethylene evaporates rapidly and produces temperatures low enough for compressed air to be liquefied; the evapora- tion of the liquefied air thus obtained produces still lower temperatures, and in this manner the most refractory gases may be liquefied. When liquefied carbonic acid is forced, by the pressure of its own vapor, in a fine stream into the air, it evaporates so rapidly that a portion of the stream is frozen, forming a delicate snow-like mass. Evaporation is continually going on in nature on a most gigantic scale. Vapor from the ocean is continually rising invisible in the air. Meet- ing with a colder stream of the atmosphere, or with a cold mountain ridge, it becomes condensed into mists or clouds. The fine particles of these unite into larger masses and fall as rain, hail, or snow, to be again evaporated by heat from the nnust ground, or from rivers, lakes, and seas. See I'iCIIM.NCi-I'oiNT; VAPOR. EV'ARTS, Jeremiah (1781-1831). An American editor. He was born at Sunderland, Vt., graduated at Yale in 1802, and practiced law in New Haven. He was editor for some years of the Missionary Herald, and in 1821 was chosen corresponding secretary of the American Board of Commissioners for Foreign Missions. He was an efficient advocate and organizer of Christian missions, and took an active part in the movement to secure justice for the Indian tribes. Consult Tracy, Memoirs of Jeremiah Evarts (Boston, 1845'). EVARTS, William Maxwell (1818-1901). An eminent American lawyer and statesman. He studied at the Harvard Law School until 1839. In 1841 he was admitted to the liar. He was Deputy United States District Attorney from 1849 until 1851, and District Attorney from 1851 until 1853. in 1860 he attended the National Republican Convention in Chicago as the chairman of the New York delegation, and nominated Seward for the Presidency. During the Civil War he was secretary of the Union Defense Committee, and was sent by President Lincoln on a diplomatic mission to England. He was the senior counsel nf President Johnson in the great impeachment trial of 1868 (see Johnson, Andrew), and did much to secure his acquittal. From July. 1868, until March I, 1869, he was Attornej General oi the United stales. In 1872 he acted as chief counsel of the United States before the Geneva I i of Arbitration, In the contest between Hayes and Tildes in 1 s77 for the succession to the Presidency, Evarts was the leading counsel of the Republicans In-fore the Electoral Commis- sion (q.v.). lie was appointed Secretary of stale by President Hayes, and served through- out the term. In 1881 he was sent as a dele gate of the United States lo the International l'inetai Conference at Paris, and from ISS.'i to 1891 he served in the United States Senate. He then retired both from politics and from the bar, and lived in New York City until his death. Only a few of his public addresses have been published. Among these are the eulogy on Chief Justice Chase, delivered at Dartmouth in 1873; the Centennial oration delivered in Philadelphia in 1876; and his oral ions at the unveiling of statues in New York to William Seward and Daniel Webster. EVE. The name given to the first woman, in Gen. iii. 20. The Hebrew form, Havvah, is con- nected with the verb to live, and probably means life, or perhaps a living thing. In the passage it is explained that the name was given 'because she was the mother of all living.' Unlike Adam, Eve is unquestionably a proper name. The pas- sage (Gen. ii. 18-25) in which the creation of Eve is related is assigned to the Yahwistie writer, and lays stress upon the close relation between Adam and Eve and between husband and wife. Verse 24 has been thought to reflect the primitive or- ganization of society, where kinship is traced through the maternal line. See Adam, and con- sult Robertson Smith. Kinship and Marriage in Early Arabia (Cambridge, 1885). EVE, Paiti, Fitzsimmons (1806-77). An American physician. He was born in Augusta, Ga., and graduated at the University of Georgia in 1*26 and at the University of Pennsylvania Medical College in 1828. He then studied in Europe for several years, and acted as surgeon in the Polish Revolution of 1831, receiving a cross of honor in recognition of his services. He was professor of surgery in several colleges in this country, and published a number of interesting papers. EVECTION (Lat. evectio, a carrying upward, from evehere, to carry out, from c, forth -{-veil to carry). A lunar perturbation or inequality depending upon the alternate increase and de- crease of the eccentricity of the moon's orbit. (See Lunar Theory.) Evection may change the moon's place as much as 1.25°, and alter the time of occurrence of an eclipse as much as six hours. EVELYN, John (1620-1706). An English author, born October 31, 1620, at Wotton, the family seat. Surrey. Educated first at the free school of Lewes, he was afterwards for a short time at Balliol College, Oxford, and also studied at the Middle Temple. During the Civil War he found it prudent to pass much of his time on the Continent, though he served in the King's army for three days (1642), and lived in England for two years i Sept ember. 1647. to June. 16491. Re- turning to England in 1652, he settled at Saves Court, Deptford, where he lived quietly, amus-
