* Hence with diffusive salt. 1. 119. Salts of various kinds are produced from the recre∣ments of animal and vegetable bodies, such as phosphoric, ammoniacal, marine salt, and others; these are washed from the earth by rains, and carried down our rivers into the sea; they seem all here to decompose each other except the marine salt, which has there∣fore from the beginning of the habitable world been perpetually accumulating.

There is a town in the immense salt-mines of Cracow in Poland, with a market∣place, a river, a church, and a famous statue, (here supposed to be of Lot's wife) by the moist or dry appearance of which the subterranean inhabitants are said to know when the weather is fair above ground. The galleries in these mines are so numerous and so intricate, that workmen have frequently lost their way, their lights having been burnt out, and have perished before they could be found. Essais, &c. par M. Macquart. And though the arches of these different stories of galleries are boldly executed, yet they are not dangerous; as they are held together or supported by large masses of timber of a foot square; and these vast timbers remain perfectly sound for many centuries, while all other pillars whether of brick, cement, or salt soon dissolve or moulder away. Ibid. Could the timbers over water-mill wheels or cellars, be thus preserved by occasionally soaking them with brine? These immense masses of rock-salt seem to have been produced by the evaporation of sea-water in the early periods of the world by subterranean fires. Dr. Hutton's Theory of the Earth. See also Theorie des Sources Salees, par Mr. Struve. Histoire de Sciences de Lausanne. Tom. II. This idea of Dr. Hutton's is confirmed by a fact mentioned in M. Macquart's Essais sur Minerologie, who found a great quantity of fossil shells, principally bi-valves and madre-pores, in the salt-mines of Wialiczka near Cracow. During the evaporation of the lakes of salt-water, as in artificial salt-works, the salt begins to crystallize near the edges where the water is shallowest, forming hollow inverted pyramids; which, when they become of a certain size, subside by their gravity; if urged by a stronger fire the salt fuses or forms large cubes; whence the salt shaped in hollow pyramids, called flake-salt, is better tasted and preserves flesh better, than the basket or powder salt; because it is made by less heat and thence contains more of the marine acid. The sea-water about our island contains from about one twenty-eighth to one thirtieth part of sea-salt, and about one eightieth of magnesian salt. See Brownrigg on Salt. See note on Ocymum, Vol. II. of this work.

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