The originators of Babylonian astronomy were not the Chaldaeans, but another race from the mountains of Elam, who are generally called Acadians. Of the astronomy of this race we have no complete records, but can only judge of their progress by the words and names left by them to the science, as afterwards cultivated by the Semitic Babylonians. These last were a subsequent race, who entering the country from the East, conquered the original inhabitants about 2000 B.C., and borrowed their civilization, and with it their language in the arts and sciences. But even this latter race is one of considerable antiquity, and when we see, as we shortly shall, the great advances they had made in observations of the sun and moon, and consider the probable slowness of development in those early ages, we have some idea of the remoteness of the date at which astronomical science was there commenced. Our chief source of information is an extremely ancient work called The _Observations of Bell_, supposed to have been written before 1700 B.C., which was compiled for a certain King Saigou, of Agave in Babylonia. This work is in seventy books or parts, and is composed of numerous small earthen tablets having impressed upon them the cuneiform character in which they printed, and which we are now able to read. We generally date the art of printing from Caxton, in 1474, because it took the place of manuscript that had been previously in use in the West; but that method of writing, if in some respects an improvement on previous methods of recording ideas as more easily executed, was in others a retrogression as being less durable: while the manuscripts have perished the impressions on stone have remained to this day, and will no doubt last longer than even our printed books. These little tablets represented so many leaves, and in large libraries, such as that from which those known have been derived, they were numbered as our own are now, so that any particular one could be asked for by those who might wish to consult it. The great difficulty of interpreting these records, which are written in two different dialects, and deal often with very technical matters, may well be imagined. These difficulties however have been overcome, and a good approach to the knowledge of their contents has been made. The Chaldaeans, as is well known, were much given to astronomy and many of their writings deal with this subject; but they did practical work as well, and did not indulge so much in theory as the Aryans. We shall have future occasion in this book to refer to their observations on various points, as they did not by any means confine themselves to the simplest matters; much, in fact, of that with which modern astronomy deals, the dates and duration of eclipses of the sun and moon, the accurate measurement of time, the existence of cycles in lunar and solar phenomena, was studied and recorded by them. We can make some approach