Investigations which have been made among the ruined cities of Chaldea have given great weight to the authority of Berosus, and are tending to the confirmation of his history. In Susiana there was found a Cushite inscription, mentioned by Rawlinson, in which there is a date that goes back nearly to the year 3200 B. C. The testimony of the records disentombed from the ruins, as well as Berosus, contradicts the prevalent hypothesis that the Magian or Aryan race occupied the country before the Cushites. These ruins also "confirm Berosus by showing that Chaldea was a cultivated and flourishing nation, governed by kings, long previous to the time when the city known to us as Babylon rose to eminence and became the seat of empire. During that long time there were several great political epochs in the history of the country, representing important dynastic changes, and several transfers of the seat of government from one city to another. Such epochs in Chaldean history are indicated by the list of Berosus."[99] By this people, the science of astronomy was well understood. "Callisthenes, who accompanied Alexander to Babylon, sent to Aristotle from that capital a series of astronomical observations which he had found preserved there, extending back to a period of one thousand nine hundred and three years from Alexander's conquest of the city.... These observations were recorded in tablets of baked clay.... They must have extended, according to Simplicius, as far back as 2234 B. C., and would seem to have been commenced and carried on for many centuries by the primitive Chaldean people." A lens of considerable power, used for either magnifying or condensing the rays of the sun, was found at Babylon, in a chamber of the ruin called Nimroud.[100] _China._--Litse, an eminent Chinese historian, relates that there were long periods of time when the Chinese kingdom flourished, the chronology of which is not preserved, although there is recorded some knowledge of the rulers. One of these rulers promoted the study of astronomy. Next come the historical epochs. During the first, astronomy, religion, and the art of writing were cultivated. This was a great epoch, and ruled by fifteen successive kings. In the second epoch, agriculture and medical science were promoted. In the third, the magnetic needle was discovered, the written characters improved, civilized life advanced, and a great revolt suppressed. In the fourth and fifth epochs, the descendants of the previous ruler reigned. Next came the period of Yao and Shin. After this the period of the "Imperial Dynasties," which began with the Emperor Yu, who lived two thousand two hundred years B. C. The historical work of Sse-ma-thi-an narrates events chronologically from the year 2637 B. C. to 122 B. C.[101]