[20] Sal-gem;—a name given to a kind of salt harder than common salt, and which sometimes has the transparency and colour of precious stones. It is found invariably in the same soil as gypsum, in the neighbourhood of which constant observation has proved it to be never wanting; and even the strata of salt and gypsum frequently alternate. The sal-gem forms itself sometimes into large undivided beds, sometimes it runs in large detached cubes, behind beds of clay and rock. The mines (I may say the quarries) of sal-gem are found at every height, and now and then on a level with the plains. In all parts of the known world no production of nature is more abundant than salt. Most of the sal-gem mines in Spain and England are of several hundred feet extent. The town of Cardona in Spain is situated at the foot of a rock of solid salt, rising almost perpendicular to the height of four or five hundred feet, without interstice, fissure, or separate layer. This immense mass of salt is about a league in circuit: its depth, and consequently the bed on which it rests, is unknown. From top to bottom the salt is of the purest white, or of a light transparent blue. This prodigious mountain of salt, quite free from gypsum and other extraneous matter, is the only one of the kind in Europe. In the county of Chester in England, near the Irish sea, is a very extensive mine of sal-gem behind a ledge of rock; and after having worked through twenty-five feet of salt, in several places of a fine deep red, from twelve to fifteen feet of rock again appeared, and salt under that; a fact which destroys the hypothesis of sal-gem being produced from saline lakes dried up.—Dictionary of Natural History.
[21] Sea Dog; a sea fish; partakes in some respects of the nature of the shark.—See Dictionary of Natural History.
[22] Gypsum.—A mineral substance composed of chalk and sulphurous acid: in strictness it may be considered as a neutral salt; but being soluble only in a small degree, and having the external character of stone, mineralogists class it as a stony substance. It has abundance of varieties.
[23] Black Swan;—Discovered by M. de la Billardiere on a lake of New Zealand.
[24] Beast with a bill.—This singular creature was, like the last, discovered in a lake of New Zealand; a particular account of it may be found in Blumenbach’s Natural History, published in Germany.
[25] Arcadia, according to the poets was the most beautiful and the happiest of all countries.
THE END.
Printed by Richard and Arthur Taylor, Shoe-Lane, London.