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After the death of Demetrius, king of Syria, whose kingdom was divided by his sons Demetrius and Antiochus, a little before the Achaean War, a comet blazed forth not inferior to the sun in size. Its orb was at first fiery red, and emitted a bright light sufficient to dispel the darkness of night. By and by its size was gradually reduced and its brightness waned. Finally it went completely out. How many stars, suppose you, would require to combine to make up such a huge mass? You might collect in one a thousand of them without ever matching the size of the sun. In the reign of Attalus a comet appeared, moderately small in size to begin with. By and by it mounted up and spread out and moved as far as the equator, equalling in the extent of its immense length the whole quarter of the sky which we call the Milky Way. How many planets must have combined to occupy with an unbroken line of fire such a long tract of the sky?