The model completed, most of the carving is done by a skilled laborer, the sculptor taking it up to give the finish, which a master-hand alone can bestow. The copying of the model into marble is accomplished by means of a method of mechanical measurement, or “pointing.” The model and the block of marble are both fastened to a base called a “scale-stone,” to which a standard vertical rod can be attached at corresponding centers, having at its upper end a sliding needle, so adapted by a movable joint as to be set at any angle and fastened by a screw when so set. The master sculptor having marked the governing points with a pencil on the model the instrument is applied to these and the measure taken. The standard being then transferred to the block-base, the pointer, guided by his measure, cuts away the marble, taking care to leave it rather larger than the model, so that the general proportions are kept, and the more important work is then left for the master hand. The character of work is influenced by the nature of the material in which the sculptor carves; the harder the stone the more difficult to give it the pliant forms of life. It is remarkable that the most ancient and perfect Egyptian statues should have been formed of very hard stones; and, as the ancient Egyptians were not acquainted with steel, they must have been dependent upon bronze, of various degrees of hardness, for their cutting tools. These works are remarkable for their excellence, both of form and proportion, and in the finish given to the details of feature, the dress, and the ornaments. Assyrian sculpture was in softer stones, limestones and alabaster; only small objects, such as seals, being worked in hard stones. Greek and Roman sculptors made many statues and bas-reliefs in hard stones, such as basalt, granite, and porphyry. The extreme difficulty of such work may be understood when it is seen that the ordinary method of the chisel and mallet, in the most skillful hands, would be quite unavailing in this hard material. The treadle-wheel, the drill, and the file, are brought to aid the chisel, and even these require the use of emery upon the wheel of the lapidary, in the manner in which the hardest stones are cut. Clay modeled and dried in the sun, or hardened by the fire, was naturally one of the early forms in which sculpture was developed. At once ready to hand, and easily modeled, it was adopted for the same reasons that made clay convenient for the ordinary vessels of every-day use. We find countless numbers of these baked, or sun-dried clay figures. They have escaped destruction because of the little value of the material and because they resist decay. The Egyptians and Assyrians applied a vitreous glaze to terra-cotta objects, which made them more decorative and more durable.