The poem discovered by George Smith is written out on twelve tablets, each of which is a separate book or chapter of the whole. There is an astronomical work in over seventy tablets. The first of them begins with the words: "_When the gods Anu and ..._" These words are taken as the title of the entire series. Each tablet bears the notice: First, second, third tablet of "_When the gods Anu and ..._" To guard against all chance of confusion, the last line of one tablet is repeated as the first line of the following one--a fashion which we still see in old books, where the last word or two at the bottom of a page is repeated at the top of the next. [Illustration: 49.--ANTIQUE BRONZE SETTING OF CYLINDER. (Perrot and Chipiez.)] [Illustration: 50.--CHALDEAN CYLINDER AND IMPRESSION.(Perrot and Chipiez.)] [Illustration: 51.--ASSYRIAN CYLINDER. (Perrot and Chipiez.)] 15. The clay tablets of the ancient Chaldeans are distinguished from the Assyrian ones by a curious peculiarity: they are sometimes enclosed in a case of the same material, with exactly the same inscription and seals as on the inner tablet, even more carefully executed.[U] It is evidently a sort of duplicate document, made in the prevision that the outer one might be injured, when the inner record would remain. Rows of figures across the tablet are impressed on it with seals called from their shape cylinders, which were rolled over the soft moist clay. These cylinders were generally of some valuable, hard stone--jasper, amethyst, cornelian, onyx, agate, etc.,--and were used as signet rings were later and are still. They are found in great numbers, being from their hardness well-nigh indestructible. They were generally bored through, and through the hole was passed either a string to wear them on, or a metal axis, to roll them more easily.[V] There is a large and most valuable collection of seal cylinders at the British Museum. Their size ranges from a quarter of an inch to two inches or a little more. But cylinders were also made of baked clay and larger size, and then served a different purpose, that of historical documents. These are found in the foundations of palaces and temples, mostly in the four corners, in small niches or chambers, generally produced by leaving out one or more bricks. These tiny monuments range from a couple of inches to half a foot in height, seldom more; they are sometimes shaped like a prism with several faces (mostly six), sometimes like a barrel, and covered with that compact and minute writing which it often requires a magnifying glass to make out. Owing to their sheltered position, these singular records are generally very well preserved. Although their original destination is only to tell by whom and for what purpose the building has been erected, they frequently proceed to give a full though condensed account of the respective kings' reigns, so that, should the upper structure with its engraved annals be destroyed by the