529 



CAMBRIC. 



CAMEO. 



530 



cochinchensia of Louriero), as the source of the Siam camboge ; while 

 that of Ceylon is stated to be obtained from the Xanthochymus ovali- 

 folius. (Roxb.) Others assign the Ceylon camboge to the Mangostana 

 Morella. (Derous. in Lamarck, ' Encyclo.' vol. iii. p. 701.) This last 

 point it is of less importance to settle, if the statement of Dr. Christison 

 be correct, that Ceylon camboge is not now an article of European com- 

 merce, all that is found in the markets of this country coming from 

 China. 



From the bruised leaves and young branches of the first-mentioned 

 tree flows a yellow juice, which is received in cocoa-nut shells or 

 earthen vessels ; it is then allowed to thicken, and afterwards formed 

 into rolls. This is the finest sort, called the pipe camboge of Siam. 

 A portion is formed into round cakes, which are either entire or have 

 a hole in the centre. This is the cake camboge of Siam. 



The juice from the Xanlhochymm ovalifoliwi flows spontaneously, but 

 sparingly ; it is increased by incisions in the stem, and by kindling 

 fires in the vicinity of the tree. The colour of both kinds differs 

 according to the season of the year, the age, and part of the tree from 

 which the juice is obtained. The Siam camboge occurs in pieces of 

 variable size, externally of a dirty yellowish brown colour, covered with 

 a fine yellow powder. When broken they exhibit a conchoidal or 

 vitreous fracture, with a brown or saffron-yellow colour. 



At the ordinary temperature of the air camboge has little smell, but 

 when heated it gives out a very peculiar one. Taken into the mouth 

 it has scarcely any perceptible taste, but upon being chewed for some 

 time it causes a sharp, somewhat acrid feeling, ending in a sweet 

 sensation, accompanied with dryness in the mouth. It excites after- 

 wards a flow of saliva, which is coloured yellow. Its specific gravity 

 is 1'207. A specimen of pipe camboge of Siam, analysed by Dr. Chris- 

 tiaon, yielded as follows : 



Pipe Camboge of Siam. 

 Resin . . 74-2 

 Arabin . . . 21'8 

 Moisture . . 4'8 

 Woody fibre, a trace. 



Cake Camboge of Siam. 

 Resin . . 64'8 

 Arabin . . 20'2 

 Fecula . . 5-6 

 Lignin . . 5'3 



Moisture . . 4'1 



Of Ceylon camboge one specimen yielded 



Resin ..... 75'5 



Arabin 18'3 



Cerasin ..... 0'7 



Moisture . . . . 4'8 



The cake camboge is not entirely a natural production, but a manu- 

 factured article. 



Camboge is almost entirely soluble in alcohol, and is not precipitated 

 from solution by the addition of water. With water it forms an 

 emulsion in which the resin is kept suspended by the gum. It is 

 soluble in the alkalies. The resin may be considered its active prin- 

 ciple. It is remarkable that a substance possessed of such slight 

 sensible qualities, having no smell, and scarcely any taste, should be so 

 powerful in its action on the human frame. It is a drastic purgative ; 

 and in combination with alkalies, forms a most powerful hydragogue 

 cathartic, occasioning numerous copious watery motions. In an over- 

 dose it causes excessive purging, sometimes vomiting ; and if taken in 

 large quantity, it produces inflammation of the intestines, mortification, 

 and death. 



The diseases in which it is most useful are ascites, or dropsical 

 accumulations in the cavity of the abdomen, especially if accompanied 

 with obstructions in the liver, or other abdominal viscera. It ha.s also 

 been employed against the tape-worm, and obstinate or habitual con- 

 stipation. The doses must be carefully regulated, and only taken by 

 the order of an intelligent and responsible medical attendant. Its use 

 as a quack medicine has led in many cases to fatal results. 



Yellow juices, which when inspissated form a substance resembling 

 camboge, arc obtained from several trees, both of the tribe of Guttifenc 

 and Hypericaceao. Garcinia pictoria is stated by Mr. Royle (' Flora of 

 the Himalaya/ p. 132) to yield a camboge, which in its crude and 

 unprepared state is superior to every other kind ; but it is not so 

 permanent. The Garcinia celebica (Linn.) likewise furnishes some. 

 Several species of Vismia (Hypericacea?) yield an American camboge of 

 good quality ; V. sessilifolia (Pers.), V. guianensis (Pers.), V. cayen- 

 (Pers.), V. micrantfia (Mart.), Vismia baccifera (Mart.). The 

 Hypericum pomiferum (Roxb.) also yields a sort of camboge ; and the 

 Argeinone mexican.i. 



ilioge is more extensively used as a pigment than as a medicine. 



An artificial camboge is manufactured with turmeric and other 

 materials. This should always bo rejected. 



CAMBRIC is one of the numerous varieties of flax or linen manu- 

 factured. It is supposed to have derived its name from having been 

 first made at Cambray. It bears much the same relation to linen that 

 muslin does to calico, being a very fine and thin fabric. Scotch 

 cambric, now manufactured in l;irge quantities, is a kind of imitation 

 cambric, made from fine hard-twisted cotton. The French material 

 Ijatittt if a sort of Scotch cambric, to which dyes and printed colours 

 are applied. 



French cambrics are imported and Scotch cambric exported to some 

 extent, but do not figure largely in the Board of Trade returns. 



ARTS AND 8CI. DIV. VOL. II. 



CAMELLIA JAPONICA, or Japan Hose. The botanical description 

 of this plant has been given in the NAT. HIST. DIV. [CAMELLIA.] 



All the varieties of Camellia Japonica succeed best when treated as 

 conservatory plants ; that is, planted in the open border under glass, 

 protected from frost, and freely exposed to light and air. They then 

 grow into large evergreen bushes, covered with a dense foliage, upon 

 which their gaudy flowers are beautifully relieved, and are far handsomer 

 objects than when their roots are confined within the narrow compass 

 of a garden-pot. Many of the varieties are nearly hardy, that is, they 

 can bear the ordinary winters of England almost without protection ; 

 but then they are so very inferior to conservatory specimens, as to be 

 little worth the having as out of door shrubs, unless upon our south- 

 west coast, in some of the warm bays of Devonshire and Cornwall. 

 They are multiplied by cuttings, grafts, and buds, and also by seeds ; 

 there are hundreds of varieties ; the best are the double-white, the 

 double-stripe (with the Donkdarii, which has a red and white stripe 

 in a different style), the C. mi/rtifulia, Ckandlerii, and pnnctata. They 

 thrive best in half loam from rotted turfs, and half turfy peat, broken 

 up very fine. After they have bloomed, or even while flowering, 

 buds will be formed for the succeeding season. These, when forming 

 at the top, or on long straggling branches, should be carefully pinched 

 off, in order to induce the plant to become thick and bushy, as well as 

 to prevent its wasting its strength ; while all the buds that are well- 

 placed should remain. After Ihe plant has done flowering, it should 

 be pruned of all useless or unsymmetrical branches. If they require to 

 be shifted from one pot to a larger, this is the time for doing so. The 

 plants may then remain in the greenhouse, where they should be 

 secured plenty of air, but shaded from the sun during the hottest parts 

 of the day, until they have made their growth. They should now be 

 placed out of doors, sheltered from the mid-day sun, and guarded from 

 high winds, until it is time to return them to the conservatory, which 

 is about the month of September, so as to avoid the effects of the 

 early frosts. 



The Camellia reticulata, one of the finest species . of the genus, 

 remarkable for its net-marked leaves, and its semi-double rose-coloured 

 flowers, can only be brought to perfection by being treated as a conser- 

 vatory plant, and planted in a pit or greenhouse, in the open mould. If 

 confined in a pot, its leaves are apt to become white and unhealthy. 

 If placed in a bright hothouse, its leaves and flowers are rendered much 

 deeper-coloured, but altogether smaller, and the shoots more stunted. 

 This sort will not easily propagate, either by buds, or cuttings, or grafts, 

 like the common camellia, but requires to have its young wood inarched 

 upon healthy young camelh'a stocks, when it takes freely ; but the 

 parent plant, if many of its shoots are thus treated, suffers so much 

 from the mutilation attendant upon the process, that it is two or three 

 years before it is sufficiently recovered to submit again to the operation. 



CAMELOPA'RDALUS, the canielopard or giraffe, a constellation 

 formed by Hevelius. A line drawn from Capella to the pole-star 

 passes right through the body of the constellation : the hind part 

 precedes in right ascension, of which the whole ranges from four to 

 eight hours. The letters are of course not in Bayer. The following 

 are the principal stars : 



No. in Catalogue 



of British 



Character, Association. Magnitude. 



1058 4 



1062 4 



a 1474 4 



b 1504 4 



1536 4 



CAMEO, a gem or stone engraved in rillevo ; that is, in wlu'ch the 

 object represented is raised above the plane of the ground, in contra- 

 distinction to INTAGLIO, in which the subject is incised, or indented : 

 strictly speaking the term cameo refers to such stones only as have 

 strata or grounds of different colours. There has been much unsatis- 

 factory discussion respecting the origin and exact meaning of the word 

 cameo, and Ducange, Lessing, and others have quoted various ways of 

 writing it. 



The art of engraving stones is of high antiquity : but it was at the 

 arlier periods, for the most part confined to intaglio, or indenting, a 

 simpler and an easier process than relieving the work from a ground ; 

 and as such stones were used for signets or seals in very remote ages 

 ^Exod. xxviii. 11, 21, &c.), the intaglio mode of working seems to be 

 ;he most natural as well .as the best adapted to the purpose. For 

 intaglios, transparent stones of a single colour, or at most clouded 

 stones (as the agates), were used ; but for cameos, stones variegated in 

 colour, or with colour in thin strata, as the onyxes and sardonyxes, 

 wore employed ; artificial stones were also used. 



It has been supposed that the Etruscans had the art of engraving 

 iard stones before it was known to the Greeks ; and from the forma 

 resembling those of the scarabcei of the Egyptians, it has been thought 

 that the Etruscans derived their knowledge from Egypt. Many en- 

 graved stones however that are called Etruscan, are doubtless early 

 Greek, as may be inferred from their subjects, and from the occurrence 

 in the inscriptions of characters of a Greek form. 



The earliest Greek artist distinctly mentioned as an engraver of 

 stones, is Theodorus of Samos; Herodotus (iii. 41) tells us that the 

 famous ring of Polycrates " was the work of Theodorus, the son of 



