longitudinal direction, and plates or pieces of the same material, having sockets in them to receive the ends or shoulders of the pipes, placed transversely, and extending from one side of the bridge to the other, so that when the requisite number of pipes, &c. are put together, they form the arch so firmly as not to require the aid of screws, bolts, cramps, or any iron fastening whatever; but the joints should be closed with lead or cement.
When applied to warehouses and other buildings, Mr. Wyatt's invention consists in forming arched cielings of cast iron, and supporting them and the floors by hollow pillars, or cylinders, of the same material. It ought to be remarked, that the number of sockets in the transverse iron plates, should always correspond with the number of ribs in the arch.
Various other kinds of bridges are constructed, according to the purposes for which they are designed, such as pendent or hanging-bridges, draw-bridges, floating-bridges, and those made of copper, or wooden-boats fastened with stakes or anchors, and covered with planks; but as the description of them would swell this article to an undue length, and as they are not immediately connected with subjects of economy, we shall content ourselves with having given the preceding account of bridges in general.
BRINE, or Pickle, is water saturated with saline particles. It is either native, as the sea-water; or factitious, when formed by a solution of salt in water.
Pickle made according to the common rule, that it should bear an egg, may be sufficiently strong to preserve substances intended for early use. A true pickle, however, for preserving meat, fish, and butter, during a long voyage, ought to be boiled down till the salt begins to crystallize, which is discoverable by a thin scum on the surface of the liquid while it continues over the fire. The water being then completely saturated with salt, the pickle is perfect.
In the salt-works at Upwick, in Worcestershire, a pit yields at the same time three sorts of brine, of different degrees of strength. This pit is worked by a pump, and the strongest salt first brought up from the bottom, is called first man; the next, which is of an inferior quality, is denominated middle man; and the third, or weakest, last man.
Leach brine is what drops from the granulated salt in drying: it is preserved and boiled a second time, being stronger than the brine of the pit. The species of sand found in the Staffordshire brines, after coction, is supposed by naturalists to be produced by that operation, as it was not previously found in the water.
Brine-pan, a place where salt-water is confined and exposed to the heat of the sun, by which salt is obtained by evaporation.
Brine-springs, those saline fountains which yield water for the manufacture of salt. It is supposed that the saline spring at Namptwich, in Cheshire, would be sufficient to yield salt for the consumption of the whole kingdom.
Besides this, there are several other remarkable brine-springs in England, particularly that of East-Chennock, in Somersetshire, which rises twenty miles from the sea; and another at Barrowdale, near Keswick, in Cumberland. The
