Page:EB1911 - Volume 05.djvu/821

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CHABAZITE—CHABOT

the political atmosphere of Ceylon has remained undisturbed since the deportation of the last king of Kandy.

Authorities.—Major Thomas Skinner, Fifty Years in Ceylon, edited by his son, A. Skinner (London, 1891); Constance F. Gordon Gumming, Two Happy Years in Ceylon (2 vols., Edinburgh, 1892); H. W. Cave, The Ruined Cities of Ceylon (London, 1897), and The Book of Ceylon (London, 1908); Sir Emerson Tennent, Ceylon (2 vols. 4th ed., 1860); J. Ferguson, Ceylon in 1903 (Colombo); J. C. Willis, Ceylon (Colombo, 1907). See also E. Müller, Ancient Inscriptions in Ceylon, published for the government (1883–1884), and the important archaeological survey in Epigraphia Zeylonica, part i., 1904, ii., 1907, iii., 1907, by Don Martino de Silva Wickremasinghe, who in 1899 was appointed epigraphist to the Ceylon government. Among other works on special subjects may be mentioned H. Trimen, F.R.S., director of Ceylon Botanic Gardens, Ceylon Flora, in 5 vols., completed by Sir Joseph Hooker; Captain V. Legge, F.Z.S., History of the Birds of Ceylon (London, 1870); Dr Copleston, bishop of Colombo, Buddhism, Primitive and Present, in Magadha and in Ceylon (London, 1892); review by Sir West Ridgeway, Administration of Ceylon, 1896–1903; Professor W. A. Herdman, Report on the Pearl Oyster Fisheries, 1903–1904.

CHABAZITE, a mineral species belonging to the group of zeolites. It occurs as white to flesh-red crystals which vary from transparent to translucent and have a vitreous lustre. The crystals are rhombohedral, and the predominating form is often a rhombohedron (r) with interfacial angles of 85° 14′; they therefore closely resemble cubes in appearance, and the mineral was in fact early (in 1772) described as a cubic zeolite. A characteristic feature is the twinning, the crystals being frequently interpenetration twins with the principal axis as twin-axis (figs, 1, 2). The appearance shown in fig. 1, with the corners of small crystals in twinned position projecting from the faces r of the main crystal, is especially characteristic of chabazite. Such groups resemble the interpenetrating twinned cubes of fluorspar, but the two minerals are readily distinguished by their cleavage, fluorspar having a perfect octahedral cleavage truncating the corners of the cube, whilst in chabazite there are less distinct cleavages parallel to the rhombohedral (cube-like) faces. Another type of twinned crystal is represented in fig. 2, in which the predominating form is an obtuse hexagonal pyramid (t); the faces of these flatter crystals are often rounded, giving rise to lenticular shapes, hence the name phacolite (from φακός, a lentil) for this variety of chabazite.

EB1911 - Twinned Crystals of Chabazite.jpg
Fig. 1. Fig. 2.
Twinned Crystals of Chabazite.

The hardness of chabazite is 4½, and the specific gravity 2.08-2.16. As first noticed by Sir David Brewster in 1830, the crystals often exhibit anomalous optical characters: instead of being uniaxial, a basal section may be divided into sharply-defined biaxial sectors. Heating of the crystals is attended by a loss of water and a change in their optical characters; it is probable therefore that the anomalous optical characters are dependent on the amount of water present.

Besides phacolite, mentioned above, other varieties of chabazite are distinguished. Herschelite and seebachite are essentially the same as phacolite. Haydenite is the name given to small yellowish crystals, twinned on a rhombohedron plane r, from Jones’s Falls near Baltimore in Maryland. Acadialite is a reddish chabazite from Nova Scotia (the old French name of which is Acadie).

Chemically, chabazite is a complex hydrated calcium and sodium silicate, with a small proportion of the sodium replaced by potassium, and sometimes a small amount of the calcium replaced by barium and strontium. The composition is however variable, and is best expressed as an isomorphous mixture of the molecules (Ca, Na2) Al2(SiO4)2 + 4H2O and (Ca, Na2) Al2(Si3O8)2 + 8H2O, which are analogous to the felspars. Most analyses correspond with a formula midway between these extremes, namely, (Ca, Na2)Al2(SiO3)4 + 6H2O.

Chabazite occurs with other zeolites in the amygdaloidal cavities of basaltic rocks; occasionally it has been found in gneisses and schists. Well-formed crystals are known from many localities; for example, Kilmalcolm in Renfrewshire, the Giant’s Causeway in Co. Antrim, and Oberstein in Germany. Beautiful, clear glassy crystals of the phacolite (“seebachite”) variety occur with phillipsite and radiating bundles of brown calcite in cavities in compact basalt near Richmond, Melbourne, Victoria. Small crystals have been observed lining the cavities of fossil shells from Iceland, and in the recent deposits of the hot springs of Plombières and Bourbonne-les-Bains in France.

Gmelinite and levynite are other species of zeolites which may be mentioned here, since they are closely related to chabazite, and like it are rhombohedral and frequently twinned. Gmelinite forms large flesh-red crystals usually of hexagonal habit, and was early known as soda-chabazite, it having the composition of chabazite but with sodium predominating over calcium (Na2, Ca)Al2(SiO3)46H2O. The formula of levynite is CaAl2Si3O10 + 5H2O.  (L. J. S.) 


CHABLIS, a town of north-central France, in the department of Yonne, on the left bank of the Serein, 14 m. E. by N. of Auxerre by road. Pop. (1906) 2227. Its church of St Martin belongs to the end of the 12th century. The town gives its name to a well-known white wine produced in the neighbouring vineyards, of which the most esteemed are Clos, Bouguerots, Moutonne, Grenouille, Montmaires, Lys and Vaux-Désirs. There are manufactures of biscuits.


CHABOT, FRANÇOIS (1757–1794), French revolutionist, had been a Franciscan friar before the Revolution, and after the civil constitution of the clergy continued to act as “constitutional” priest, becoming grand vicar of Henri Grégoire, bishop of Blois. Then he was elected to the Legislative Assembly, sitting at the extreme left, and forming with C. Bazire and Merlin de Thionville the “Cordelier trio.” Re-elected to the Convention he voted for the death of Louis XVI., and opposed the proposal to prosecute the authors of the massacre of September, “because among them there are heroes of Jemmapes.” Some of his sayings are well known, such as that Christ was the first “sans-culotte.” Compromised in the falsification of a decree suppressing the India Company and in a plot to bribe certain members of the Convention, especially Fabre d’Eglantine and C. Bazire, he was arrested, brought before the Revolutionary Tribunal, and was condemned and executed at the same time as the Dantonists, who protested against being associated with such a “fripon.”


CHABOT, GEORGES ANTOINE, known as Chabot de l’Allier (1758–1819), French jurist and statesman, was president of the tribunal of Montluçon when he was elected as a deputy suppléant to the National Convention. A member of the council of the Ancients, then of the Tribunate, he was president of the latter when the peace of Amiens was signed. He had a resolution adopted, tending to give Napoleon Bonaparte the consulship for life; and in 1804 supported the proposal to establish a hereditary monarchy. Napoleon named him inspector-general of the law schools, then judge of the court of cassation. He published various legal works, e.g. Tableau de la législation ancienne sur les successions et de la législation nouvelle établie par le code civil (Paris, 1804), and Questions transitoires sur le code Napoléon (Paris, 1809).


CHABOT, PHILIPPE DE, Seigneur de Brion, Count of Charny and Buzançais (c. 1492–1543), admiral of France. The Chabot family was one of the oldest and most powerful in Poitou. Philippe was a cadet of the Jarnac branch. He was a companion of Francis I. as a child, and on that king’s accession was loaded with honours and estates. After the battle of Pavia he was made admiral of France and governor of Burgundy (1526), and shared with Anne de Montmorency the direction of affairs. He was at the height of his power in 1535, and