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 β-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 (χρύσεος, 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”; εἰ μὴ γὰρ ᾐν Χρύσιππὄς, οὐκ ἂν ἠν Στοά (“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 Jahrbücher für Philologie, suppl. vol. xiv. (1885); R. Nicolai, De logicis Chrysippi libris (1859); Christos Aronis, Χρύσιππος γραμματικος (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.
CHRYSOBERYL, a yellow or green gem-stone, remarkable for its hardness, being exceeded in this respect only by the diamond and corundum. The name suggests that it was formerly regarded as a golden variety of beryl; and it is notable that though differing widely from beryl it yet bears some relationship to it inasmuch as it contains the element beryllium. In chrysoberyl, however, the beryllium exists as an aluminate, having the formula BeAl2O4, or BeO·Al2O3. The analysis of a specimen of Brazilian chrysoberyl gave alumina 78.10, beryllia 17.94, and ferric oxide 4.88%. The typical yellow colour of the stone inclines in many cases to pale green, occasionally passing into shades of dark green and brown. The iron usually present in the mineral seems responsible for the green colour. Chrysoberyl is often mistaken by its colour for chrysolite (q.v.), and has indeed been termed Oriental chrysolite. In its crystalline forms it bears some relationship to chrysolite, both crystallizing in the orthorhombic system, but it is a much harder and a denser mineral. As the two stones are apt to be confounded, it may be convenient to contrast their chief characters:—
| Chrysoberyl. | Chrysolite. | |
| Hardness | 8.5 | 6.5 to 7 |
| Specific Gravity | 3.65 to 3.75 | 3.34 to 3.37 |
| Chemical Composition | BeAl2O4. | Mg2SiO4. |
Chrysoberyl is not infrequently cloudy, opalescent and chatoyant, and is then known as “cymophane” (Gr. κῦμα, a “cloud”). The cloudiness is referable to the presence of multitudes of microscopic cavities. Some of the cymophane, when cut with a convex surface, forms the most valuable kind of cat’s-eye (see [Cat’s-eye]). A remarkable dichroic variety of chrysoberyl is known as alexandrite (q.v.).
Most chrysoberyl comes from Brazil, chiefly from the district of Minas Novas in the state of Minas Geraes, where it occurs as small water-worn pebbles. The cymophane is mostly from the gem-gravels of Ceylon. Chrysoberyl is known as a constituent of certain kinds of granite, pegmatite and gneiss. In the United States it occurs at Haddam, Conn.; Greenfield Centre, near Saratoga Springs, N.Y.; and in Manhattan island. It is known also in the province of Quebec, Canada, and has been found near Gwelo in Rhodesia.
(F. W. R.*)