At a time beyond the reach of certain history, the planets, along with the sun and moon, had been arranged in a certain recognized order by the Egyptians or some other ancient nation. Probably this arrangement had been made according to the slowness of their motions among the stars; for though the motion of each is very variable, the gradation of their velocities is, on the whole, very manifest; and the different rate of travelling of the different planets, and probably other circumstances of difference, led, in the ready fancy of early times, to the attribution of a peculiar character to each luminary. Thus Saturn was held to be of a cold and gelid nature; Jupiter, who, from his more rapid motion, was supposed to be lower in place, was temperate; Mars, fiery, and the like.[34\3] [Note 34\3: Achilles Tatius (_Uranol._ pp. 135, 136), gives the Grecian and Egyptian names of the planets. Egyptian. Greek. Saturn Νεμεσέως Κρόνου ἀστὴρ φαίνων Jupiter Ὀσίριδος Δῖος φαέθων Mars Ἡρακλεοῦς Ἀρέος πυρόεις Venus Ἀφροδίτης ἑώσφορος Mercury Ἀπόλλωνος Ἑρμοῦ στίλβων] It is not necessary to dwell on the details of these speculations, but we may notice a very remarkable evidence of their antiquity and generality in the structure of one of the most familiar of our measures of time, the _Week_. This distribution of time according to periods of seven days, comes down to us, as we learn from the Jewish scriptures, from the beginning of man's existence on the earth. The same usage is found over all the East; it existed among the Arabians, Assyrians, {128} Egyptians.[35\3] The same week is found in India among the Bramins; it has there, also, its days marked by those of the heavenly bodies; and it has been ascertained that the same day has, in that country, the name corresponding with its designation in other nations. [Note 35\3: Laplace, _Hist. Astron._ p. 16.]