We cannot easily suggest any way in which the very large slabs or plaques of ivory used by the early and mediæval artists were obtained. The leaves of a diptych of the seventh century, in the public library at Paris, are fifteen inches in length by nearly six inches wide. In the British museum is a single piece which measures in length sixteen inches and a quarter by more than five inches and a half in width, and in depth more than half an inch. By some it is thought that the ancients knew a method, which has been lost, of bending, softening, and flattening solid pieces of ivory; others suppose that they were then able to procure larger tusks than can be got from the degenerate animal of our own day. Mr. McCulloch, in his dictionary of commerce, tells us that 60 lbs. is the average weight of an elephant’s tusk; but Holtzapffel, a practical authority, declares this to be far too high, and that 15 or 16 lbs. would be nearer the average. Be this as it may, pieces of the size above mentioned (and larger specimens probably exist) could not be cut from the biggest of the tusks preserved in the South Kensington museum; although it weighs 90 lbs., is eight feet eleven inches long, and sixteen inches and a half in circumference at the centre. This tusk is the largest of five which were presented to the Queen by the king of Shoa about the year 1856, and given by Her Majesty to the museum. The other four weigh, respectively, 76 lbs., 86 lbs., 72 lbs., and 52 lbs. They are all, probably, male tusks. An enormous pair of tusks, weighing together 325 lbs., was shown in the Great Exhibition of 1851; but these, heavy as they were, measured only eight feet six inches in length, and did not exceed twenty-two inches in circumference at the base. An ingenious mode of explaining how the great chryselephantine statues of Phidias and other Greek sculptors were made, is proposed and fully explained in detail by Quatremère De Quincy in his work on the art of antique sculpture. He gives several plates in illustration, more particularly Plate XXIX.; but none of them meet the difficulty of the large flat plaques. The natural form of a tusk would adapt itself easily, so far as regards the application of pieces of very considerable size, to the round parts of the human figure.