CHRYSENE C18H12

chrysene c18h12, a hydrocarbon occurring in the high boiling fraction of the coal tar distillate. it is produced in small quantity in the distillation of amber, on passing the vapour of phenyl-naphthyl-methane through a red-hot tube, on heating indene, or by passing the mixed vapours of coumarone and naphthalene through a red-hot tube. it crystallizes in plates or octahedra (from benzene), which exhibit a violet fluorescence, and melt at 250°c. chromic acid in glacial acetic acid solution oxidizes it to chrysoquinone c18h10o2, which when distilled with lead oxide gives chrysoketone c17h10o. when chrysene is fused with alkalis, chrysenic acid, c17h12o3, is produced, which on heating gives [beta]-phenyl-naphthalene. on heating chrysene with hydriodic acid and red phosphorus to 260°c, the hydro-derivatives c18h28 and c18h30 are produced. it gives characteristic addition products with picric acid and dinitroanthraquinone. impure chrysene is of a yellow colour; hence its name ([greek: chryseos], golden yellow). chrysippus (c. 280-206 b.c.), greek philosopher, the third great leader of the stoics. a native of soli in cilicia (diog. laert. vii. 179), he was robbed of his property and came to athens, where he studied possibly under zeno, certainly under cleanthes. it is said also that he became a pupil of arcesilaus and lacydes, heads of the middle academy. this impartiality in his early studies is the key of his philosophic work, the dominant characteristic of which is comprehensiveness rather than originality. he took the doctrines of zeno and cleanthes and crystallized them into a definite system; he further defended them against the attacks of the academy. his polemic skill earned for him the title of the "column of the portico." diogenes laertius says, "if the gods use dialectic, they can use none other than that of chrysippus"; [greek: ei me gar en chrysippos, ouk an en stoa] ("without chrysippus, there had been no porch"). he excelled in logic, the theory of knowledge, ethics and physics. his relations with cleanthes, contemporaneously criticized by antipater, are considered under stoics. he is said to have composed seven hundred and fifty treatises, fragments alone of which survive. their style, we are told, was unpolished and arid in the extreme, while the argument was lucid and impartial. see g.h. hagedorn, _moralia chrysippea_ (1685), _ethica chrysippi_ (1715); j.f. richter, _de chrysippo stoico fastuoso_ (1738); f. baguet, _de chrysippi vita doctrina et reliquiis_ (1822); c. petersen, _philosophiae chrysippeae fundamenta_ (1827); a. gercke, "chrysippea" in _jahrbucher fur philologie_, suppl. vol. xiv. (1885); r. nicolai, _de logicis chrysippi libris_ (1859); christos aronis, [greek: chrysippos grammatikos] (1885); r. hirzel, _untersuchungen zu ciceros philosophischen schriften_, ii. (1882); l. stein, _die psychologie der stoa_ (1886); a.b. krische, _forschungen auf dem gebiete der alten philosophie_ (1840); j.e. sandys, _hist. class. schol._ i. 149.