Besides slabs and cylinders, the written memorials of Assyria comprise inscribed bulls and lions, stone obelisks, clay tablets, bricks, and engraved seals. Tin seals generally resemble those of the Chaldaeans, which have been already described: but are somewhat more elaborate, and more varied in their character. [PLATE XXXIX., Fig. 2.] They do not very often exhibit any writing; but occasionally they are inscribed with the name of their owner, while in a few instances they show an inscription of some length. The clay tablets are both numerous and curious. They are of various sizes, ranging from nine inches long by six and a half wide, to an inch and a half long by an inch wide, or even less. [PLATE XL., Fig. 2.] Sometimes they are entirely covered with writing; while sometimes they exhibit on a portion of their surface the impressions of seals, mythological emblems, and the like. Some thousands of them have been recovered; and they are found to be of the most varied character. Many are historical, still more mythological; some are linguistic, some geographic, some again astronomical. It is anticipated that, when they are deciphered, we shall obtain a complete eneyclopaedia of Assyrian science, and shall be able by this means to trace a large portion of the knowledge of the Greeks to an Oriental source. Here is a mine still very little worked, from which patient and cautious investigators may one day extract the most valuable literary treasures. The stone obelisks are but few, and are mostly in a fragmentary condition. One alone is perfect--the obelisk in black basalt, discovered by Mr. Layard at Nimrud, which has now for many years been in the British Museum. [PLATE XL., Fig. 1.] This monument is sculptured on each of its four sides, in part with writing and in part with bas-reliefs. It is about seven feet high, and two feet broad at the base, tapering gently towards the summit, which is crowned with three low steps, or gradines. The inscription, which occupies the upper and lower portion of each side, and is also carried along the spaces between the bas-reliefs, consists of 210 clearly cut lines, and is one of the most important documents that has come down to us. It gives an account of various victories gained by the monarch who set it up, and of the tribute brought him by several princes. The inscribed lions and bulls are numerous. They commonly guard the portals of palaces, and are raised in a bold relief on alabaster slabs. The writing does not often trench upon the sculpture, but covers all those portions of the slabs which are not occupied by the animal. It is usually a full account of some particular campaign, which was thus specially commemorated, giving in detail what is far more briefly expressed in the obelisk and slab inscriptions.