The tablet (K. 382) seen in Fig. 48, B, is a good example of a clay tablet bearing the impress of a cylinder-seal. The tablet, which measures 4-1/8 inches by 2-5/8 inches, contains the terms of a contract. The impression itself shows us a mythological four-winged being, such as is seen so often on Assyrian bas-reliefs. In either hand he holds a bird by the leg. The cylinders by the side of the tablet are reproduced to actual size; A, C, and D (Brit. Mus. Nos. 89319, 89538, 101974) illustrate the divergence of size which the Babylonian cylinder-seals exhibit, (C) being an unusually large specimen, and (D) an exceptionally small example, the vast majority of seals occupying an intermediate position between these two extremes; in (A) we have a cylinder in which the metal handle is still preserved. The existence of the same kind of seal in Egypt as early as the time of the first dynasty has been used as an argument in support of the theory that the primitive civilizations of Egypt and Babylonia were to some extent interdependent. It is true that cylinder-seals could only be of use where clay was employed as a writing-material, but there is no direct evidence that the practice of using clay for either writing or building purposes was borrowed from Babylonia, while the similarity in shape of early Babylonian and Egyptian mace-heads is an even more uncertain argument whereon to base an otherwise unsupported theory. The materials used in the manufacture of cylinder-seals were many and various. The earliest known material is shell, but the most frequently occurring is hæmatite. Among other materials used may be mentioned serpentine, marble, quartz crystal, chalcedony, carnelian, agate, jasper, syenite, jade, obsidian, onyx, limestone, schist, mother of emerald, and amethyst. A few flint cylinders have been recovered, but this material was evidently but seldom employed, while glass is of even rarer occurrence, and metal is unknown. The process by which the required device was engraved upon the cylinder depended upon the material of which the latter was made. The softer materials employed in earlier times, such as shell, marble or serpentine, were possibly engraved with tools made of flint, but the harder stones would require an implement made of some more stubborn material. Ward is of opinion that either emery or a certain stone called corundum was used for the purpose. The latter was employed at a very early period in Egypt and in later times in Greece. The earliest seals appear to have been entirely made by hand, the practice of drilling by means of a bowstring not being introduced till a later period. Within the confines of a single chapter it will of course be quite impossible to review all the innumerable types of cylinder-seals used by the Babylonians and Assyrians of different ages, and we can therefore only single out one or two examples of some of the more interesting classes as being fairly representative of the periods to which they belong.