“The Chaldaeans and Babylonians, as is well known, excelled especially in the cognate sciences of arithmetic and astronomy. On the broad and monotonous plains of Lower Mesopotamia, says Professor Rawlinson, where the earth has little to suggest thought or please by variety the ‘variegated heaven,’ ever changing with the times and the seasons, would early attract attention, while the clear sky, dry atmosphere, and level horizon, would afford facilities for observations so soon as the idea of them suggested itself to the minds of the inhabitants. The records of these astronomical observations were inscribed in cuneiform character on soft clay tablets, afterwards baked hard and preserved in the royal or public libraries in the chief cities of Babylonia. Large numbers of these tablets are now in the British Museum. When Alexander the Great took Babylon, it is recorded that there were found and sent to Aristotle a series of astronomical observations extending back as far as the year B.C. 2234. Recent investigations into the nature of these records render it probable that upon them rests the entire structure of the metric system of the Babylonians. The day and night were divided by the Babylonians into 24 hours, each of 60 minutes, and each minute into 60 seconds—a method of measuring time which has never been superseded, and which we have inherited from Babylon, together with the first principles of the science of astronomy. The Babylonian measures of capacity and their system of weights were based, it is thought, upon one and the same unit as their measures of time and space, and as they are believed to have determined the length of an hour of equinoctial time by means of the dropping of water, so too it is conceivable that they may have fixed the weight of their _talents_, their _mina_, and their _shekel_, as well as the size of their measures of capacity, by weighing or measuring the amounts of water, which had passed from one vessel into another during a given space of time. Thus, just as an hour consisted of 60 minutes and the minute of 60 seconds, so the talent contained 60 minae, and the mina 60 shekels. The division by sixties or sexagesimal system, is quite as characteristic of the Babylonian arithmetic and system of weights and measures, as the decimal system is of the Egyptian and the modern French. And indeed it possesses one great advantage over the decimal system, inasmuch as the number 60, upon which it is based, is more divisible than 10.