Vases in the shape of an earthen oil jar, or of the line l d n, fig. 278, could be made from a cone such as op, with a bottom soldered in: these preparations would save the work of the hammer, although such forms and others far more difficult could be raised entirely by the hammer from a flat piece of metal.

Should any of the above vessels require a solid thickened edge or lip, beyond that which would result from the drawing-in of the metal, it would be necessary to select a piece of metal of smaller diameter but thicker, and to retain the margin of the full thickness by directing all the blows within the same; sometimes on the other hand, works require to be thinned on the edge, these arc then cut out proportionally smaller than their intended sizes, as illustrated by the following example, which is considered the most difficult of its kind.

London; they are strengthened by a most judicious inner framing of copper and wrought-iron bars, stays, bolts, and nuts, extending through the arms and downwards into the building; thus adding about 2 tons of iron to the load of copper and to the 38 ounces of gold used in its decoration.

The hell of of a French horn, together with the first coil of the tube, are made of a flat strip of metal about 1 feet long and

2 inches wide; for making the bell of the instrument, there is an enlargement at one end of the strip, in the form of the funnel piece 206, page 382, and of the width of 16 to 22 inches, the smaller piece being adopted when the bell is required to be very thin. The narrower piece of metal, when first bent up, much resembles the butt end of a musket, terminating in a small tube; the metal is united and soldered down the edge with a cramp or dovetail joint, fig. 248, page 398; it is next thrown into a conical form of about five inches diameter, and expanded from within, first with blows of a wooden mallet upon a wooden block, and then with those of a hammer on iron stakes.

When nearly finished, or about one foot diameter, it is hammered very accurately upon a cast-iron mould turned exactly to the form of the bell, which is thus rendered much thinner than the general substance, and remarkably exact; the band containing the wire for stiffening the edge of the bell, is attached by dexterous hammering and without solder. To bend the tube to the curve without disturbing its circular section, it is filled with a cement, principally pitch, which allows the tube to be bent to the scroll of the instrument, without suffering the metal to be puckered or disturbed from its true circular section; and in bending similar tubes to smaller curves, they are filled with lead. These materials serve as flexible and fusible supports, which are easily removed when no longer required.

Should any of the raised works have ornamental details, such as concave or convex flutes, or other mouldings, they would be mostly overlooked until the general forms had been given; and then every little part would be proceeded with upon the same principles of solid and hollow blows. Each of the series of flutes would be first slightly developed all around the object, then more fully, and so on until the completion: when, however, the details are so large as to form what may be considered integral parts, it is necessary to prepare for them at an earlier stage.

Thus, to take an excellent, familiar, and agreeable example, let fig. 279 represent plans, 280 sections, and 281 elevations of jelly moulds, many of which require the greatest skill of the coppersmith. The general outline is that of a cylinder abcd, upon a larger cylinder efg h, as a base. The twelve large and deeply indented flutes or finials, rise perpendicularly to a great height from the plane surfaces a c and e b, and yet the whole is hammered out of one flat plate.

Figs. 279.

Circular Works Spun In The Lathe Part 5 100128


Circular Works Spun In The Lathe Part 5 100129


Circular Works Spun In The Lathe Part 5 100130

The first step is to raise the summits of the flutes i or k, preparatory to the general formation of the upper cylinder abcd, and then the two are worked up together, leaving for a time the expanded base efg h, but ultimately the whole receive a general attention in common. If the flutes were polygonal, and terminated in ornaments like spires or finials, as at k, they would be first treated as if for the more simple or generic form i, and the details would be subsequently produced.

I have before me a mould which consists of two series of polygonal flutes, such as k, rising one above the other, and ending in pyramids which altogether present the appearance of a beautiful and symmetrical group of crystals; this was produced in the same general manner, by external blows, and almost without the employment of compasses or measuring instruments.

Those moulds which require an inner tube, (the Turk's cap of the confectioner,) although for economy usually made in two parts, may be made in one. In this case the tube would be first raised in the center of a flat plate, beginning from a very small hole, the edge of which would be first curled up perpendicularly, and then the flat disk would be driven downwards by blows within the angle, throwing part of its central substance into the body of the tube; after the completion of which the surrounding parts would be raised as before described, but the process would be difficult, from the narrow space for the stakes or inner tools, The skill called for in such works is greatly enhanced by the attention which is required to preserve a nearly uniform thickness in the metal, notwithstanding the apparent ore to which it is submitted; and this is only endured in consequence of a frequent recurrence to the process of annealing, which reinstates the malleable proper

In cases of extensive repetition, or where large numbers of any specific shape are required, expensive dies of the exact forms employed; but these arc only applicable to objects in small relief, and to those in which the parts arc not quite perpendicular. Dies would be entirely inapplicable to objects such as the jelly moulds, fig. 280, although a common notion exists that they are rapidly made by that method, but which is in genual utterly impossible when such objects arc made in one piece. In all such cases, the metal has to undergo the same bendings and stretchings between the dies as if worked by the hammer, and which unless gradually brought about, are sure to cut and rend the metal; the production of many such forms with dies is therefore altogether impracticable.

Figs. 282.

Circular Works Spun In The Lathe Part 5 100131


Circular Works Spun In The Lathe Part 5 100132

For example, the patera or moulding, z, fig. 282, is only in small relief, and yet the flat piece of metal a, would be cut in or more parts if suddenly compressed between the dies A, B; as the edges i,j, would first abruptly bend and then cut the metal, without giving it the requisite time to draw in, or to ply itself gradually to the die, beginning at the center as in the process of hammering.

In fig. 283, the successive thicknesses obliterate the effect of the actue edges of the bottom die B; the face and back of every thickness differ, as although parallel they are not alike, but they become gradually less defined, so that in fig. 283, the top die A, requires nothing more than a flowing line with slight uudulations.

Therefore, when two or three dozen plates are inserted between the dies A, B, the transition from a to z is so gradual, that the metal can safely proceed from a to b, from b to c, and so on, and it will be progressively drawn in and raised without injury. When one or two pieces alone are required, they are blocked-down to fit the mould, by laying above them a thick piece of lead, which latter is struck with the mallet or hammer; by the yielding resistance the lead opposes, the thin metal is drawn into the die with much less risk of accident, than if it were subjected to the blows without the intervention of the lead.

In producing many pieces, however, one piece a, is added at the top, between every blow, and one piece z, is also removed from the bottom; occasionally two, three or more are thus added and removed at one time, and generally as the concluding step, every piece is struck singly between dies, such as fig. 282, which exactly correspond. In general the process of annealing must be also resorted to once or more frequently during the transition from a to z. For the best works the bottom die is mostly of hardened steel, sometimes of cast iron, or hard brass; the top die is also of hardened steel in the best works, but in very numerous cases lead is used, from the readiness with which it adapts itself to the shape required.

Stamping is very common for many works in brass, but which would be inapplicable if the pieces had perpendicular and lofty sides, as in fig. 280, page 408: such lines, although rounded by the successive thicknesses of metal, would still present perpendicular sides, and therefore render this mode of treatment with dies impracticable, without reference to cost. Thimbles are raised at five or six blows, between as many pairs of conical dies successively higher, but the metal requires to be annealed every time. See note A C, page 974, Appendix, Vol. II.