INDENE

indene, c9h8, a hydrocarbon found in the fraction of the coal tar distillate boiling between 176° and 182° c., and from which it may be extracted by means of its picrate (g. kramer, a. spilker, ber., 1890, 23, p. 3276). it may also be obtained by distilling the calcium salt of hydrindene carboxylic acid, c6h4(ch2)2·ch·cooh. it is an oil which boils at 179.5°-180.5°, and has a specific gravity 1.04 (15° c.). dilute nitric acid oxidizes it to phthalic acid, and sodium reduces it in alcoholic solution to _hydrindene_, c9h10. a. v. baeyer and w. h. perkin (ber., 1884, 17, p. 125) by the action of sodiomalonic ester on ortho-xylylene bromide obtained a hydrindene dicarboxylic ester, c6h4(ch2br)2 + 2chna(co2c2h5)2 = 2nabr + ch2(co2c2h5)2 + c6h4:[ch2]2:c(co2c2h5)2; this ester on hydrolysis yields the corresponding acid, which on heating loses carbon dioxide and gives the monocarboxylic acid of hydrindene. the barium salt of this acid, when heated, yields indene and not hydrindene, hydrogen being liberated (w. h. perkin, _jour. chem. soc._, 1894, 65, p. 228). indene vapour when passed through a red hot tube yields chrysene. it combines with nitrosyl chloride to form indene nitrosate (m. dennstedt and c. ahrens, _ber._, 1895, 28, p. 1331) and it reacts with benzaldehyde, oxalic ester and formic ester (j. thiele, _ber._, 1900, 33, p. 3395). on the derivatives of indene see w. v. miller, _ber._, 1890, 23, p. 1883; th. zincke, _ber._, 1887, 20, p. 2394, 1886, 19, p. 2493; and w. roser and e. haselhoff, _ann._, 1888, 247, p. 140. indenture (through o. fr. _endenture_ from a legal latin term _indentura_, _indentare_, to cut into teeth, to give a jagged edge, in _modum dentium_, like teeth), a law term for a special form of deed executed between two or more parties, and having counterparts or copies equal to the number of parties. these copies were all drawn on one piece of vellum or paper divided by a toothed or "indented" line. the copies when separated along this waved line could then be identified as "tallies" when brought together. deeds executed by one party only had a smooth or "polled" edge, whence the name "deed poll." by the real property act 1845, § 5, all deeds purporting to be "indentures" have the effect of an "indenture," even though the indented line be absent. the name "chirograph" (gr. [greek: cheir], hand, [greek: graphein], to write) was also early applied to such a form of deed, and the word itself was often written along the indented line (see further deed and diplomatic). the term "indenture" is now used generally of any sealed agreement between two or more parties, and specifically of a contract of apprenticeship, whence the phrase "to take up one's indentures," on completion of the term, and also of a contract by labourers to serve in a foreign country or colony (see coolie).