Plainly, if the “scientiam” here spoken of refers to the invention of Lysistratus, and is interpreted to be the art of casting in plaster, it is ridiculously incorrect to say that it was older than casting in brass. If that invention be of modeling in plaster, it is also entirely incorrect. We know that this was practiced at least a century previous,—as, for instance, in the construction of the great statue of Zeus at Megara, the body of which was of plaster and clay, the head alone being cased in gold and ivory; and also of the Bacchus in painted plaster, of which Pausanias speaks. The only way in which we can explain the statement that any “scientiam” or process described by Pliny as used by Lysistratus was older than the art of casting in bronze, is by supposing he meant to say that the process he employed was in itself an old one, and that it was only in the practical application to the making of portraits that there was any novelty,—the process of covering a core of plaster with wax being older than casting in bronze, while covering a sketch of plaster with wax and then working that surface up from life was new. The statement so understood would be intelligible at least, and, as far as we know, perfectly correct. The method of the ancients in casting bronze statues is not described by any ancient writer, but it is supposed to have been this: A fire-proof core was first built up of plaster, clay, earth, or other materials, and over this a thin and even coating of wax or pitch was spread; or perhaps, which is not so probable, the surface was rasped down to the thickness intended for the bronze, and afterwards covered with a thin coating of wax. In either case the result would be the same. The outside of this wax being then completely covered with sand or packed clay-dust, there would be a thin coating of wax inclosed between the two surfaces, which, melting away before the fused metal, would allow that metal to take its place. This would account for the remarkable thinness and evenness of the ancient bronzes; for by such a method the core would be perfect, and the artist would naturally put on as little wax as possible. If we suppose the statue, after it was nearly completed in plaster or clay, not to have been rasped down but simply to have been covered with wax, we shall see that the result would be that the bronze cast would be a little fuller in size and thicker in proportions than the original model. And this is a peculiar characteristic of the ancient bronzes, especially to be observed in the limbs and joints, which are generally larger and puffier in bronze than in marble statues.