SELECTION 



SELENIUM 



305 





He sat as a lay-meml>er in the Assembly of 

 Divines at Westminster (1643), and perplexed 

 his clerical colleagues sadly with his irony and 

 his learning. Soon after he was appointed 

 keeper of the rolls and records in the Tower. In 

 1644 he was appointed one of the twelve com- 

 missioners of the Admiralty, aud elected master 

 of Trinity Hall at Cambridge, which office he 

 declined. In 1646 he subscribed the Covenant, 

 and the year after the sum of 3000 was voted to 

 him by parliament in consideration of his services 

 and sufferings. In 1647 he was appointed one of 

 the university visitors, and always used his in- 

 fluence to moderate the tyranny of his fanatical 

 colleagues. One of his last public acts was to join 

 in the last effort for a reconciliation between the 

 kin^ and the parliament. After the execution of 

 Charles, of which it is certain he strongly dis- 

 approved as both unlawful and inexpedient, he 

 took little share in public matters ; and when 

 requested by Cromwell to answer the Eihin 

 Basilike, he refused. His death occurred at 

 Whitefriars, November 30, 1654, and he was 

 buried in tiie Temple Church, London. His last 

 years he had spent in the house of Elizabeth, 

 dowager-countess of Kent, with whom, between 

 her husband's death in 1639 and her own in 1631, 

 the intimacy had been so great as to colour 

 Aubrey's statement that they were privately 

 married. He left about 40,000 ; his 8000 books 

 were given by his executors to the Bodleian. The 

 principal writings of Selden, liesides those already 

 mentioned, are : Marmora Aruiuleliana ( 1628) ; De 

 SuccesxionHiu.i in Bona Defuncti strundum Leget 

 Ebratorum (1634); De Jure Naturali et Gentium, 

 iuxta Disciplinam Ebrteorum ( 1640), a work more 

 learned than critical, like most of Selden's bibli- 

 cal productions, who thought far too much of the 

 opinions of the Rabbins ; Uxor Ebraica ; and 

 De Synedriis et Prafectiiris Juridicis Ebrce- 

 uriim (1650 et teq.); besides a great variety of 

 posthumous tracts and treatises, of which" the 

 most famous, and also the most valuable, is his 

 Table-talk, recorded and published by his aman- 

 uensis, Richard Milward, in 1689 (ed. by Singer, 

 lM47,and by Reynolds, 1892). Of this Coleridge says, 

 with some exaggeration, however : 'There is more 

 weighty bullion sense in this book than I can find in 

 the same number of pages of any uninspired writer.' 

 Selden's best character stands in the gallery of 

 Clarendon, who adds excellently : ' His style in 

 all his writings seems harsh, and sometimes 

 obscure ; which is not wholly to be imputed to the 

 abstract subjects of which he commonly treated, 

 out of the paths trod by other men, but to a little 

 undervaluing the beauty of a style, and too much 

 propensity to the language of antiquity ; but in his 

 conversation he was the most clear discourser, and 

 had the best faculty in making hard things easy 

 and present to the understanding, of any man that 

 hath been known.' Selden's works were collected 

 and published at London in three folio vols. (1726). 

 See Singer's Biographical Preface, Dr John Aikin's 

 Livtt of Seldm and Uhtr ( 1811 ), and G. \V. Johnson's 

 Memoir ( 1835). The Helilun Society was founded in 1887 

 for promoting the study of English legal history. 



Selection. See DARWINIAN THEORY, SEXUAL 



SKI.KI-I ION. 



Selectmen. See MASSACHUSETTS. 



Selene, the Greek moon-goddess, a daughter 

 of Hyperion and Theia, and sister of Helios 

 <the Sun) and Eos (the Dawn). As sister of 

 Helios or Phoiboa ( ' shining') she had the name of 

 Phtxhe, and latterly was identified with Artemis, 

 though the identification was never quite exact, 

 Artemis always retained her reputation for 

 chastity, while Selene had fifty daughters by her 



lover Endymion and seveial by Zeus. She is 

 represented by the poets as n lovely woman with 

 long wings and a golden diadem, riding across the 

 heavens in a chariot drawn by two wTiite horses, 

 cows, or mules. See Ueber Seletie und Verwandtes, 

 by W. H. Koscher (1890). 



Sclcnua. a river (740 miles) of Mongolia and 

 Siberia, flowing by three arms into Lake Baikal. 

 It is navigable from May till October for 200 

 miles from the Chinese frontier, and steamers and 

 lighters ply on it. 



Selenite (Gr. Selene, 'the moon'). This name 

 is given to the transparent variety of Gypsum 

 (q.v. ). It occurs in distinct crystals belonging to 

 the oblique or monoclinic system, or in folia. It is 

 usually white (colourless), but sometimes it is 

 tinged with red, yellow, green, gray, &c. Selenite 

 is soft, easily cut, and capable of 'being split into 

 very thin plates. These are much used in polaris- 

 ing apparatus (see POLARISATION). Selenite is a 

 comparatively common mineral, although it rarely 

 occurs in large quantities. Finely crystallised 

 specimens are found at Bex in Switzerland, in 

 Si.'ily, and at different places in the United States. 

 There is a magnificent group of crystals of this 

 mineral in the British Museum from Reinhards- 

 brunn in Gotha. In Nova Scotia, where, in the 

 vicinity of Oxford, near River Philip, there are 

 vast deposits of gypsum (large quantities of which 

 are sent to the United States), selenite is found 

 abundantly. At Petitcodiac, New Brunswick, 

 where extensive deposits of gypsum also occur, 

 there is a vein of nearly pure selenite one mile 

 long and eight feet wide. Selenite, being a pure 

 form of gypsum, is used for making the finest kind 

 of plaster of Paris. Plates of selenite are said to 

 have been used by the ancients for some of the 

 purposes for which we use glass. 



Selenium (.ym. Se; at. wt. 79) is an element 

 having two forms. In the vitreous form, at ordinary 

 temperatures, it is a solid of a dark-brown colour, 

 and when broken presents a conchoidal vitreous 

 fracture ; thin splinters of it are, however, of a 

 dark-red tint when seen by transmitted light. It 

 is tasteless and inodorous, a non-conductor of elec- 

 tricity. Its specific gravity is 4 '28; its melting- 

 point is 217 C., and its boiling-point 700 C. When 

 selenium is very slowly cooled from the fused con- 

 dition iu appearance is quite different ; the struc- 

 ture being gran ular or crystalline ( sometimes called 

 'metallic ). Crystalline selenium is of a dull 

 leaden colour; it is very opaque to light even in 

 thin films; its specific gravity is 4'8, its melting- 

 point 200 C., and its boiling-point 680 C. It is a 

 conductor of electricity at ordinary temperatures. 

 Its resistance to the passage of an electric current 

 diminishes up to the point of fusion, but suddenly 

 increases as the selenium becomes liquid. Another 

 property of crystalline selenium, which has recently 

 given it a new interest, is that it is remarkably 

 sensitive to light ; and its electrical resistance 

 varies very much according to its exposure to light, 

 being much less in the light than in the dark. It 

 was in virtue of this property that the experiments 

 were made which led in 1880 to the discovery of 

 the Photophone ,( q. v. ). The vapour of selenium is 

 inodorous and deep yellow ; it is 164 times as heavy 

 as hydrogen at 1400 C. ; this corresponds nearly 

 to the molecular formula Sej. When heated in the 

 air selenium does not very readily take fire ; but 

 it is combustible, and burns with a blue flame, 

 while a portion of it is volatilised in red fumes. 

 The products of combustion are oxide of selenium 

 and selenious anhydride, SeOj. 



Selenium is of rare occurrence in nature ; it is 

 chiefly found as a selenide in combination with 

 lead, silver, copper, or iron ; but it has also been 



