The step from one of these processes to the other does indeed seem so evident, so natural, almost so inevitable, that we are puzzled to imagine how they could ever have overlooked it. Yet there is little doubt that they did. But from the simple fact of stamping in clay or plaster to the complex process of making moulds and casts in the round requires not one step but many, and each one of them requires calculation and invention. Indeed, if the art were now to be lost, it would be easy to conceive that centuries might pass before it would be reinvented. In the collection of Mr. Fol of Rome, of which we have heretofore spoken, there are some interesting fragments of ancient statuettes in the round, very carefully finished in plaster, being the leg and thigh of one, and the half-breast and a portion of the torso of another. These are as carefully finished as if they were in marble, but they are elaborately worked by hand in the plaster, and not cast. These are exceedingly interesting as showing the method of the ancients in working in plaster, and they clearly illustrate the process of Lysistratus as described by Pliny,—the only difference being that the surface is of gypsum and not of wax, or color. The interior or core of these fragments, which is solid, is of lime, or a coarse kind of gypsum, and over the surface of this core is spread a thin coating of fine gypsum, which has been elaborately worked and smoothed on while it was fluid. The touches and creases on the surface are those of a modeler’s hand and stick, and it differs in every way from a cast. It is therefore plain that the artist first made a core, or rough “imaginem” or “formam,” of coarse gypsum, and that he improved, emended, and finished the surface, not by means of “cera infusa in eam formam gypsi,” but of gypsum spread over it,—just as Lysistratus did. The language of Pliny is an exact description of this process. Again, a strong negative indication that gypsum was not used for casting, or indeed to any extent in modeling, is to be found in the chapter by Pliny on gypsum. “Its use is,” he says, “to whitewash [or parget], and to make small figures to ornament houses, and for wreaths.” He also adds that it is a good medicine for pains in the stomach; but he entirely omits to mention that it was ever used for casting. Is it possible to believe that if it were so used he would not have alluded even to such a fact? Would it be conceivable that at the present day a chapter could be written on plaster of Paris, omitting its employment for the purpose of casting? After giving us this enumeration of the uses to which gypsum is applied, Pliny goes on to describe its nature, tell where it is found, and name the different kinds; and he concludes with no allusion to any other use than what he has previously stated.