INTA`GLIO. This name is given to small works of the gem class, in which the design is indented or engraved, to distinguish them from those in which the subject or device is raised, called Cameos. The Greeks carried this branch of the fine arts to the same perfection which their genius and feeling for the beautiful ena bled them to reach in all others to which they devoted their attention ; but we do not trace its existence among them to a very remote date. We have no information respecting the process by which the ancient intagliatori (or sculptores) executed works which are now justly referred to as the best examples of the art. The modern practice of cutting stones in intaglio is by an apparatus similar in prin ciple to the turning lathe, which gives the cut ting tool, placed horizontally, a quick rotatory motion, and, the stone on which the design is to be engraved being brought in contact with it, the surface is ground away or indented, till the effect required is produced. Instruments of various sizes are used, which can easily be removed and replaced, and it is usual, during the process of engraving, to supply the points of the tools with diamond dust mixed with a little sweet oil. As the work proceeds, proofs
are occasionally taken in wax.
Die-Sinking or the engraving of dies is an important branch of the art of intaglio, and requires great care and skill for its perfection. The die is made of finely prepared and tem pered steel. When the first intaglio, or original die, is executed, it forms a matrix (or mould), into which a conically formed. block of softer steel is compressed, the matrix first undergoing a process by which it is hardened. An impres sion taken in this way is called a puncheon. When this is completed (and frequent anneal ing, and restriking are necessary before it is perfected), the engraver retouches the work, now in relief, and gives it all the delicacy of the original model ; the metal is then har dened, and, by pressing this puncheon into other steel which is soft (by almost a repeti tion indeed of the before-mentioned process), it serves for the purpose of making the dies for coining.