The ordinary brass or copper repoussé work of our own day is either worked from the surface only by following the lines of the design drawn on the metal by a tool called a tracer, straight or curved, as may be required for straight or curved lines, although a straight tracer will follow all but very small curves. The tracer is tapped with a broad-ended hammer according to the amount of relief intended. I should have said the sheet of metal is fastened down over a sheet of lead by screws or nails to a deal board before working on. When the outlines of the design are hammered out, the background, which bumps up between the traced lines, has to be matted. This may be done by various patterned tools called matting tools. Your design, when the matting is done, will stand in low relief from its ground, and may be polished as much as desired. Although a pleasing effect of soft relief is obtained, this is not carrying the work very far, and would only satisfy amateurs. True repoussé work consists in actually modelling by the hammer and punch, and for this both for delicate and bold relief it is necessary to reverse the metal on the pitch block. This is formed of a mixture of pitch and Russian tallow sprinkled with plaster of paris, which forms a somewhat firm but easily indentable substance when warmed, and can be held together in tin trays. While the pitch is soft you must press in your metal plate the reverse side up and then beat up the hollows of the design as they have been defined by the tracer on the face of the work and which show clearly on the back. The tools used for doing this are rounded punches of various forms. The hammering is done rather persuasively, as sudden blows make sudden dents, which are not easily smoothed. Parts of the work, again, may be hammered on the surface over a lead or pitch block, or it may be hammered over a pattern carved in wood. This method is used when several forms recur, or it is desired to repeat the same pattern.
Black & white marble Roman mosaic pavement.
Baths of Caracalla.
From sketch made in 1871.
Patterns of Roman mosaic pavements.
Baths of Caracalla.
From sketches made in 1871.
Another art of very early association with Architecture is mosaic, which may be said to be perhaps the most permanent and most splendid kind of architectural decoration ever used. In the matter of marble mosaic the Romans, though not the inventors of the art, in their pavements carried it to great elaboration, and worked it in many forms, the most successful being, to my mind, the simpler forms of flat pattern-work such as are seen in the baths of Caracalla at Rome, where white marble, or black, or black or white, is very effectively used, and there are some admirable scale-pattern borders. These make more reserved and satisfactory decorations for a floor than the shaded pictorial battle-pieces and figures of gladiators such as are seen at the Borghese Villa. In the Bardo Palace Museum at Tunis there is a very fine collection of Roman mosaic pavements. There has been a very extensive revived use of marble mosaic for the covering of entrance floors and halls in our own time; but it has been rather too much of the second-hand Roman type, although at its best it is a good type, and, as we know, many original Roman examples have been discovered, so that we are not without historic models in our own country. Marble mosaic is usually somewhat limited in colour but looking to the variety and beauty of tint to be found in marbles there is perhaps more restriction than need be, as well as in type of design. I made a design for the floor of a bank at Cleveland, Ohio, when I was in the States, which I am afraid might have tried the colour-resources of the mosaicist, since I introduced a symbolical figure of Columbia coining, wrapped in a robe of stars and stripes, which, however, would look sober enough when translated into marble tones.
PATTERN OF ROMAN MOSAIC PAVEMENT,
FROM THE BATHS OF CARACALLA.