Basalt, though harder, more brittle, and less pleasing in its colours than marble, was in considerable esteem among the sculptors of antiquity, on account of its great durability. Many fine works were consequently executed by them in this stone. Pliny, who has described several, states that the columns of it were sometimes so large as to admit of several figures being wrought out of them. The Emperor Vespasian had an entire statue, accompanied by the figures of sixteen children, cut out of a single column of basalt; this statue he placed in the Temple of Peace, and dedicated it to the Nile. The famous statue of Minerva, at Thebes, is described by travellers to have been formed of basalt. Antiques of basalt are always in a much better state of preservation than those of marble. Even such as are dug out of the earth still retain their original polish; and the finest touches of the chisel upon them are still unimpaired. ──────────────────────────────────────────────────────────────────────── ─────── ORDER III.—SALINE STONES. ─────── LIME, OR CALCAREOUS FAMILY. 139. Lime, after it has been freed from extraneous matters by burning, is a mineral of whitish colour, and pungent, acrid, and caustic taste. It has the property of changing vegetable blue colours to green, and of corroding and destroying animal substances. This mineral is found in nearly every country of the globe: but, in a native state, has not hitherto been discovered except in combination with some acid.[3] The process of purifying lime, or depriving it of the acid with which it is combined, is by burning. This is done in a large kind of furnace, called a _kiln_, where the limestone and fuel are heaped in alternate layers. After it has gone through this process it is called _quick─lime_, and has the above─mentioned appearance and qualities. Footnote 3: With _carbonic acid_ (26) it forms common limestone, marble, chalk, and some other substances; with _sulphuric acid_ (24) it constitutes alabaster, or gypsum; and with _fluoric acid_ (27) it becomes that beautiful production, the Derbyshire spar.—All these, having lime for their bases, are denominated CALCAREOUS SUBSTANCES.