PIPES, or TUBES, are made of various materials and for various purposes. Thus, we have draining-pipes for agricultural and sanitary purposes, made of earthenware, Wood; and metal; pipes of various kinds of metals for a great variety of pin poses, and tobacco-pipes (q.v.) of various materials. Formerly, wooden pipes were extensively used for conveying water and for draining; but so great an improvement has been effected of late years in the manufacture of metal and earthenware pipes that they have now become exceedingly rare, and will soon disappear. For agricultural purposes, drain-tiles are made of ordinary brick-clay; and owing to the use of machinery in their manufacture, they are produced very rapidly and cheaply. They are of various sizes, hut the most general is 15 in. in length by 21- in. diameter. The operation of the drain-tile machine is to squeeze a continuous length of soft plastic clay through a ring-shaped orifice, the cen ter of which is occupied by a core or mandrel of the cite of the hollow part of the pipe. Another arrangement of the machine is to cut the pipe to the proper lengths as at passes through, and by means of a traveling-table, to carry them forward to be removed to the sheds, where they are dried, previous to being burned in the kilns.
Earthenware pipes are now made of almost every size, from an. inch or two in diameter up to the enormous size of 54 inches. They are usually made of fire-clay, and are glazed like common pottery. See the article POTTERY. They arc wider at one end, so as to form a socket to receive the end of another, and thus form a continuous tube. These are greatly used for the drainage of houses, and for severing, for which they are admirably adapted: the inner surface being glazed as well as the outer, offers no resistance to sedimentary matters, which are consequently carried away readily. These pipes are of such' great strength, many small towns in England are now sewered with them almost entirely. Another kind has been introduced for chimney flues. They are also made of fire-clay, but unglazed externally, and so thick that there is little fear of br6aking. They ate placed one on another, and are built into the walls of houses, instead of the ordinary chimneys, and in this way save much labor in building, and afford a much more effective, and easily cleaned flue. Caouteh,ouc vulcanized amt gotta perdu& are also extensively used for making pipes for a vailtety of purposes, their flexi bility rendering them very useful. Leathern pipes are used chiefly for the conveyance of water temporarily, as in the case of fire-engines: they are generally called hose. Metal pipes are made of iron, lead, tin, or na alloy of tin and lead, copper, brass, etc. Iron pipes are usually cast, and the manufacture of such pipes has become of enormous extent, in consequence of the vast works, by which almost all large towns in this king dom and in many foreign states are now supplied with waterand gas, the pipes for which are largely exported from Great Britain. A great proportion of the trade in cast-iron pipes
is carried on in Scotland. The water-wo•ks which supply the great towns of Lancashire have nearly all been furnished with pipes from Scotland; and the magnitude of the sup ply can be best understood when it is known that for the Rivington pike works, which supply Liverpool, upwards of 20 m. of iron pipes, nearly 4 ft. in diameter, are required. It would be impossible to make a correct estimate, but it has been stated, with great reason for belief, that in Great Britain the gas and water pipes laid and iu use exceed half a million of miles in length.
Pipes made from the ductile metals, such as brass, copper, and tin. are made Ly first caring an ingot of the metal into the shape shown in fig. 1, with a hole through its of the same diameter the bore of the pipe is intended to have. into this is placed an iron rod, called the mandrel (a, fig. 2), which exactly fits, and which projects slightly at the tapered end (1), fig. 2). It is then brought to the drawing-table, and here the small end with its projecting mandrel is put into a funnel-shaped hole, drilled through a steel post (a, fig. 3), so as to allow the point to be griped on the other side by a pair of pincers, at the end of a strong chain; the machine-power is then applied to the other end of the chain, and the soft metal and its mandrel are drawn through, the former being extended equally over the surface of the latter, which is then removed, and the length of pipe is complete. Some metals re- quire repeated drawing through holes, getting gradually smaller, and have to be softened or annealed at intervals, as the metal hardens under repeated drawing. In this way, brass, copper, tin, and pewter pipes are made; and a patent has also been taken out for making steel ones; hut lead pipes are made of great lengths by squeezing, the soft metal through a hole in a steel plate in which there is a fixed core or mandrel Projecting, which forms and regulates the size of the bore of the pipe. Pipes are also made from copper, brass; and malleable iron by rolling out nalTOW strips of metal, and then passiog them successively through rollers, which are deeply grooved, and which turn up the edges. A mandrel is then laid in it, and it is next passed through double-grooved rollers, which turn the edges in, and thus form a complete tube found the mandrel. The edges, however, require soldering or welding, if of iron. All boiler tubes used to be made in this way; but the method of drawing has lately been so much improved, that copper and brass pipes, or tubes, as they are frequently called, are now drawn of considerate thickness and diameter.