date of this king cannot be ascertained: we only know that he must have belonged to the old kingdom. Assyrian weights with inscriptions in the Phenician alphabet, beside the cuneiform inscriptions, are found of the eighth century B.C., the time of King Tiglath Pilesar II., Shalmanesar IV., and Sennacherib.[392] "It can be maintained with good reason," says Diodorus, "that the Chaldæans are far before all other nations in their knowledge of the heavens; and that they devoted the greatest attention and labour to this science." At an early period, by comparing the course of the sun with that of the moon, they had perceived that the sun returned to the same position after passing through about twelve cycles of the moon; hence they fixed the year at twelve months of thirty days, which they, by intercalations of various kinds, brought into harmony with the astronomical year of 365-1/4 days.[393] The observation, that the sun after a course of twelve months returns to the same constellation, led them on to determine the changing position of the sun in the other months by constellations. Thus the Babylonians marked off the constellations which seemed to touch nearest upon the course of the sun, and arrived at the signs of the ecliptic or zodiac. Each of these twelve stations through which the sun passed they again divided into thirty parts. The week they fixed at seven days by the course of the moon; to the day they allotted twelve hours, to correspond to the twelve months of the year; the hours they divided into sixty parts, and each of these sixtieths was again subdivided into sixty parts. Their measures were also duodecimal. The cubit was twenty-four finger-breadths; and on the same system, their numerals were based upon the _sossus_, or sixty,--a derivative from twelve, and the _sarus_, or square of the _sossus_. When they attempted to fix the position and intervals of the stars in the sky, the basis taken for their measurements was the diameter of the sun. They divided the daily course of the sun, like the ecliptic, into 360 parts, and then attempted to measure these at the equinox. At the moment when the sun was seen in the sky on the morning of the equinox, a jar filled with water was opened. From this the water was allowed to run into a second small jar, till the orb of the sun was completely visible; then it ran into a third and larger jar, till the sun was again seen on the horizon on the following morning. They concluded that the diameter of the sun must stand in the same proportion to the cycle it passed through as the water in the small jar stood to the water in the large one. Hence they found that the diameter of the sun was contained 720 times in its course, and this diameter they fixed at 1/30 of an hour.[394] The observation that an active foot-courier could accomplish a certain distance in the thirtieth part of an equinoctial hour, and thirty times as much in the whole hour, supplied the Chaldæans with a