CARBAZOTIC ACID CARCASSONNE. 



359 





CARBAZOTIC ACID; an acid discovered by 

 Welter, and sometimes called Welter's Bitter. It 

 has been chiefly studied by Gay-Lussac, Dumas, 

 and Liebig. It is formed by the action of nitric 

 acid on indigo, aloes, silk, and some other or- 

 ganic substances. It forms yellow, shining scales, 

 soluble in water, to which they give an intense 

 yellow colour and a very bitter taste. It forms 

 yellow crystallizable salts with the bases. That 

 with potash is so sparingly soluble that a solution 

 of carbazotic acid in alcohol may be used as a 

 test for that alcali. The name is derived from its 

 composition, which exhibits a large proportion of 

 carbon and azote. According to Liebig, it con- 

 tains, carbon 31-457, azote 14-766, oxygen 53-777. 



CARBONIFEROUS FORMATION. The car- 

 boniferous series of strata, in geology, is so called 

 because a large proportion of vegetable and animal 

 carbon pervades the rocks composing it. It in- 

 cludes the mountain limestone, coal measures and 

 shales, and sandstone conglomerates. Carbonifer- 

 ous or mountain limestone exists in extensive beds 

 immediately below the strata containing coal, and 

 above the gray wacke series. It is of a compact 

 structure, varying from a light gray to a dark 

 brown, or bluish black colour ; is disposed in strata, 

 and these alternate with clay, slate, or an impure 

 limestone, called by the workmen blaes. This 

 limestone is full of the remains of marine shells 

 and animals, so much so as in many cases to appear 

 entirely composed of such materials. It thus ap- 

 pears to have formed the bottom and shores of a 

 former ocean, although now the strata are found 

 broken up from their original horizontal position, 

 forming the sides and summits of mountains, fre- 

 quently of considerable height. The fossil remains 

 consist chiefly of encrinites, orthoceratites, pro- 

 ductus, spirifer, tenebratula. Beds of fresh water 

 shells, and the remains of fishes and plants, have 

 also been discovered in this limestone, affording 

 proofs that lakes and rivers must have existed at the 

 period of its formation. Mountain limestone lies 

 below the coal strata of the south and south-west 

 of Scotland ; stretches into the north and western 

 counties of England, forming mountains of consi- 

 derable height; and is found to prevail in many 

 parts of the continent of Europe and in North 

 America. Lead ore is found abundantly in this 

 limestone. Many of its varieties receive a fine 

 polish, and are used as marble for domestic orna- 

 ments. It is of various colours, according to the 

 substance cjntained in it, and is variegated by ma- 

 rine shells, alumina, iron, and other minerals. A 

 dark blue or black variety is called Lucullite, from 

 Lucullus, the Roman general. It is used extensively 

 for domestic and agricultural purposes, after having 

 been burnt in kilns. By this process the animal 

 and vegetable matters which impart to it a dark 

 colour tire destroyed, and it becomes a pure white. 

 The carboniferous sandstone consists of alternate 

 beds of a white yellow or reddish colour, varying 

 in thickness from five to ten and twenty feet, with 

 beds of shale and coal interspersed. Below the 

 coal seams is found a band of dark heavy matter, 

 containing iron, called from its property of resisting 

 great heat, fire clay. The carboniferous sandstone 

 has evidently owed its origin to the decomposition 

 of granite and primary schists, for it exhibits a 

 compound of those ingredients, worn into minute 

 nodules; sometimes these are of such a size as to 

 form millstone grits and anglomerates. The de- 

 posit has usually been formed in hollow troughs or 



basins, and in the deepest pints extends to 2 or 

 3000 feet. The alternative of shale, coal, and 

 sandstone strata, prevalent throughout all this 

 series, indicates a periodical deposition. There are 

 often appearances of drifting or sudden accumula- 

 tion of large masses of the sandstone, where large 

 trees of forty and fifty feet have been carried down 

 and lodged transversely across the strata. The 

 vegetables discovered in the coal strata consist of 

 a variety of species, many of them differing from 

 plants at present in existence, and all of them in- 

 dicating a tropical nature. They chiefly consist of 

 plants allied to ferns, reeds and some species of 

 palms. Of the trees, the greater part belong to 

 the coniferae or pine tribe. These coniferae resem- 

 ble the auraucarias of New Holland and South 

 America, much more than any pines at present, 

 natives of our northern regions. There is a 

 marked similarity between the fossil plants of the 

 coal measures in every different region of the globe 

 hitherto investigated, so much so that the fossils of 

 the torrid and temperate zones are identical with 

 those found in Melville island and Greenland. 

 After the deposition of the coal seams in their 

 varied horizontal position, the beds have suffered 

 many convulsive disruptions, by which the contin- 

 uity of the strata has been greatly interrupted, and 

 many faults or slips formed, as well as portions of 

 the seams elevated to the surface of the soil. 

 Iron ore, either in beds, or nodules, or flat bands, 

 is a usual accompaniment of coal strata. 



CARCASSONNE; a town in the south of 

 France, situated in the department of Aude, and on 

 the banks of the river which gives name to the de- 

 partment. It lies due south from Paris, at the dis- 

 tance of about 390 miles in a direct line, or nearly 

 500 by the road. It is a place of great antiquity, 

 having existed before the campaigns of Caesar, who 

 speaks of it as one of the towns existing in Gallia 

 Ulterior. It is mentioned more than once by the 

 Roman writers of a later age. On the downfall 

 of the empire it passed successively into the hands 

 of the Visigoths, the Saracens, and the Franks ; 

 and under the rule of the last it was subject to 

 counts of its own, who established themselves in 

 this part of France, and transmitted their authority 

 to their heirs. It came into direct possession of 

 the crown of France about the middle of the 

 thirteenth century, being then ceded by its count 

 to Louis IX., or St Louis, who reigned as king of 

 France from 1226 to 1270. 



Carcassonne stands on both banks of the river 

 Aude, though the two parts into which the river 

 divides it may be considered as almost perfectly dis- 

 tinct. On the right bank is the old town, or cite, 

 half deserted ; it is surrounded by walls, the ap- 

 pearance of which sufficiently denotes their anti- 

 quity, and composed of narrow, dirty streets. It 

 contains a fine ruined castle and a cathedral; the 

 latter was erected about the end of the eleventh 

 century. On the left bank of the river is the 

 lower town, which is altogether modern, and built 

 with straight streets, crossing at right angles. It 

 has a Grande Place, planted with trees, surrounded 

 by well-built houses, and decorated in the middle 

 with an insignificant fountain, and the usual edi- 

 fices found in a middle-sized French town. Some 

 manufactures are carried on in the town; the chief 

 of them is that of woollen cloth, which was esta- 

 blished in the reign of Louis XL, and much en- 

 couraged by Colbert, the celebrated minister of 

 Louis XIV. 



