The perforated tube, (serving as the mandrel,) is first wound round with haybands, then covered with loam, and the core is turned, dried and blackwashed; the thickness is now laid on and also blackwashed, after which the object is moulded in sand. The thickness is next removed from the core, which latter is inserted in the mould, and supported therein by the two prints at the extremities, and by grains with long wires, the positions of which may be seen by the little bosses on the pipe, the metal being there made purposely thicker to avoid any accidental leakage at those parts. When pipes are cast in large quantities, they are moulded from wooden patterns in halves, so that it only becomes necessary to turn the core, and this, when made in the above manner, is sufficiently porous for the escape of the air.

The moulds for crooked pipes and branches are frequently made in halves, upon a flat iron-plate. An iron bar or templet of the curve required is fixed down, and a semicircular piece of furnaces, sometimes 105 inches bore, are made without the employment of the thickness. The case or cope is built up in the pit, and turned inside with a radius bar, and the core is erected on a plate on the floor, and turned outside to a gage; when dried it is lowered into the other by the crane. The cylinders are cast one foot or upwards longer than required, to serve as a head of metal and make the top edge sound, and thus much is cut off before they are bored.

To enable the mould to resist the great pressure of the lofty column of fluid metal, (equal at the base to near CO pounds on every square inch), the core is strengthened by diametrical iron bars entering slightly into the brickwork: the outer cylinder is surrounded at a small distance by iron rings piled on the other, the interval being rammed with sand; and stays are placed in all directions from the rings to the sides of the pit, which is either lined with brickwork, or when liable to be inundated with water, it is made of iron like a water-tight caisson.

Small cylinders are moulded in sand from wooden models, and only the cores are turned in loam; for cylinders of the smallest size the cores are made of sand in core boxes as already explained.

wood, called a strickle, is used for working and smoothing the half core; next a larger strickle is used for laying on the thick. ness, the two halves arc then fixed together by wires, and moulded from in the sand flask; the thickness is now stripped off the core, which is fixed in the mould by its extremities, and if needful, is supported also upon grains.

By the employment of these means, although the loam work requires time for the drying, yet with ordinary care an equality of thickness may be maintained, notwithstanding the complexity of the outline, and without the necessity for wooden patterns.

Very many of the large works in brass are also moulded in loam, the management being in most respects exactly the same as for iron, except that in some ornamental works wax is more or less employed, and is melted out of the moulds before the entry of the metal; a very slight view of the methods will serve as a sequel to the subject of brass founding.

Large bells arc turned in almost the same manner as iron cylinders or pans, by means of wooden templets, edged with metal and shaped to the inner and outer contour of the core and thickness. The inscription and ornaments are cither impressed within the cope, the clay of which is partially softened for the purpose, or the ornaments are moulded in wax, and fixed on the clay thickness before making the cope. Less generally the whole exterior face of the bell, or indeed its entire substance, is modelled in wax, and melted out before pouring. In any case, the concluding steps in filling up the apertures where the spindle passed, are to attach a dissected wooden pattern of the central stem and of the six cannons or ears by which the bell is slung, which parts are moulded in soft loam; and then, the parts having been dried and replaced, and the iron ring for the clapper inserted, the whole is ready for the pouring pit. The heariest bells are moulded within the pit the same as huge cylinders.

Brass guns arc also moulded in loam, and in a somewhat peculiar manner; a tapir rod of wood much longer than the gun, is wound round with a peculiar kind of soft rope, upon which the loam is put for making the rough casting model of the gun, which is turned to a templet; the work is executed over a long fire to dry it as it proceeds, and the model is made about one-third longer than the guu itself. The model when dried and blackwashed all over, is covered with a shell of loam, not less than three inches thick, secured by iron bands; the shell is also carefully dried; after this the taper bar is cautiously driven out from its small end, the coil of rope is pulled out, and so likewise is every piece of the clay model of the gun.

The parts for the cascable and trunnions, which should have been worked separately upon appropriate wooden models, are then attached to the shell. Should the gun have dolphins, or any other ornamental figures, they are modelled in wax and fixed on the clay model before the shell is formed, and are then melted out to make the required space for the metal.

When all is ready and dried, six, eight, or more of these loam cases, or shells, are sunk perpendicularly in a pit at the mouth of the reverberatory furnace, and the earth is carefully rammed around them; at the same time a vertical runner is made to every mould, to enter either at the bottom or not higher than the trunnion: the upper ends of the runners terminate in the bottom of a long trough or gutter, at the far end of which is a square hole, to receive the excess of metal.

In casting brass guns, tapping the furnace is rather a ceremony, and certainly an imposing sight: the middle and the end of the trough are each stopped by a shovel or gate held across the same; and the runners are all stopped by long iron rods, held by as many men. When all is pronounced to be ready, the stopper of the furnace is driven inwards with a long heavy bar swung horizontally by two or three men, and the metal quickly fills the trough; on the word of command, "number one, draw," the metal flows into the first mould, and fills it quickly but quietly from the bottom; the mould being open at the top, no air can be accidentally enclosed. Numbers two, three, and four are successively ordered to draw. The first shovel is then removed from the great channel, and now the guns, five to eight or ten, as the case may be, are similarly poured and filled to the level of the trough; after which the last shovel is withdrawn, and the residue of the metal is allowed to run into the square bed or pit prepared for it. The flow of metal from the furnace is regulated by the tapping bar, the end of which is taper, and is thrust more or less into the mouth of the furnace as required; the trough and runners are thus kept exactly full, which is an important point in most cases of pouring, as it prevents a current of air being carried down along with the metal.

Large bells are poured much in the same manner, except that the runners are at the top, and the metal runs from the great channel, through smaller gutters to every sunk mould, the stoppers for which are successively drawn. For quantities of brass intermediate between the charge of an ordinary crucible, and such as require the reverberatory furnace, the large ladles or shanks of the iron founder are used; the contents of four or six crucibles being poured into the shank as quickly as possible, and thence in one stream into the mould.*