ABSTRACT
The model of the heavens that Ptolemy constructed is wonderfully complex, but it begins from a simple analogy. Pythagoras had found that the chords which sound pleasing to the ear—the western ear—correspond to exact divisions of the string by whole numbers. When Pythagoras had proved the great theorem, he offered a hundred oxen to the Muses in thanks for the inspiration. It is a gesture of pride and humility together, such as every scientist feels to this day when the numbers dovetail and say, “This is a part of, a key to, the structure of nature herself.” The secret of the heavens that wise men looked for in antiquity was read by a Greek called Claudius Ptolemy, working in Alexandria about A.D. 150. A more elaborate ready-reckoner than the astrolabe is the astrological or astronomical computer, something like an automatic calendar, made in the Caliphate of Baghdad in the thirteenth century.
