SALT; SALT TRADE. The chemical nature of this invaluable substance is noticed under Sonium. We will here speak of its extraction and trade.
The principal part of the salt of England is made in the valley of thoWeaver in Cheshire. When the salt duty was repealed in 1824, there were 75 works where salt was raised in a fossil state : 31 were at Northwich, 26 at Winsford, 3 at Midcllewich, and 2 at Nantwich, all in Cheshire ; 2 were at Shirley Wich in Staffordshire ; 6 at Droitwieh in Gloucester shire ; and 2 in Durham. There were at the same time 35 works at which salt was made by evaporation from seawater, 29 of which were in Hampshire and the Isle of Wight. In Scotland, at the same time, there were 15 salt works, and in all of them salt was made from sea water. At Droitwich alone 260,000 tons of salt are made annually from the brine springs of that town. A singular feud has recently existed in the town, owing to attempts made to prevent the brine from flowing to certain salt works. Nearly the whole of the salt exported is made in Cheshire, and is sent down the river Weaver, which ' communieate.s with the Mersey, to Liverpool. The Stafford shire rock-salt is chiefly exported from Hull, and that of Gloucestershire from the port of Gloucester.
The rock-salt of Cheshire was first dis covered near Northwich, while searching for coal. It is found from 28 to 48 yards be neath the surface ; the first stratum is from 15 to 25 yards in thickness, extremely solid and hard, and resembling brown sugar candy. Many tons at a time are loosened by blasting with gunpowder. Beneath this comes a stra tum of hard stone, 25 to 35 yards in thickness ; and then is encountered a bed of perfectly white and pure salt, 40 yards thick. There are also brine springs, which appear to have been formed by springs flowing over the beds of rock-salt, and becoming saturated with the saline particles ; this brine is pumped up to the surface. The brine springs are from 20 to 40 yards in depth. The English table salt is almost entirely produced by evaporating this brine ; but a considerable portion of that which is exported is rock salt. The evapora
tion was in former times effected by the heat of the sun, but artificial heat is now employed. So far as observation has yet gone, the English supply is practically inexhaustible ; no limit is known to the extent of the beds or the I springs ; and it ought to be regarded as one of the blessings which we owe to the mineral wealth of our country that the beautiful table salt of England may be obtained at such an extremely low price as that now charged for it. One specimen of Northwich rock salt, weighing two tons, has been forwarded to the Great Exhibition.
About 70,000 tons of Cheshire salt are annually used by the alkali makers on the banks of the Tyne. It used to be conveyed round the Land's End and the south coast by ships ; but it is now sent by canal and river to Liverpool, from thence to Maryport by sea, and from thence to Newcastle by railway.
A duty of 10s. per bushel was laid on salt in 1798, which in 1805 was increased to 15s. In 1823 this duty was reduced to 2s.; and. in 1825 was wholly repealed. Salt used in the fisheries, in bleaching, or in agriculture, was nearly duty-free. The salt exported in 1849 amounted to 18,589,865 bushels.
The British government in India monopo lises both the manufacture and sale of salt. In the ten years 183G-45, the net receipts from this monopoly of home' salt, and duty on imported salt, varied from 989,389/. to 1,707,287/. annually. It is believed that a moderate duty on British salt would yield as large a revenue in the course of a few years, if the monopoly were abolished, while com merce would be benefitted by the interchange of East India sugar and other native commo dities for British salt; smuggling in which is extensively 'carried on, would cease ; and in of arbitrary and harsh restric tions, the consumer would obtain a better article at a cheaper rate.