140 Limestone family. It has generally but one colour; sometimes it is spot ted, dotted, clouded, striped, veined, and arborescent. It occurs massive. Internally it alternates from shining to glistening and glimmering, and the lustre is intermediate between pearly and vitreous. The fracture is foliated, but sometimes inclines to splintery. The fragments are blunt-edged. It occurs m distinct concretions, which are coarse, small, and fine granular: the small granular sometimes pass into compact, and then the concretions are only di stinguishable by their glimmering lustre. It is more or less translucent. It is semi-hard. It is brittle. It is easily frangible. Specific gravity, Parian Marble, 2.837G, Brisson Carrara Marble, 2.717. Scottish, 2.71C, Kirwan. 2.6»8, 2.711, Karsten. Chemical Characters. It generally phosphoresces when pounded, or when thrown on glowing coals. It is infusible before the blow pipe. It dissolves with effervescence in acids. Constituent Parts. Lime ’ - - 56.50 Carbonic acid, _ 4.3 qq Water, - . 0 .50 BucholZf in Neuen Journal der Chern. iv. s . 419. Geognostic