Page:Roman History of Ammianus Marcellinus.djvu/226

 affair to be discussed, or those things to he explained to him of which he was ignorant, he believed all the calumnies against Ursicinus, and deposing him from his office, ordered him into retirement; promoting Agilo, by a vast leap, to take his place, he having been before only a tribune of a native troop of Scutarii.

III
1. At the same time one day the sky in the east was perceived to be covered with a thick darkness, and from daybreak to noon the stars were visible throughout; and, as an addition to these terrors, while the light of heaven was thus withdrawn, and the world almost buried in clouds, men, from the length of the eclipse, began to believe that the sun had wholly disappeared. Presently, however, it was seen again like a new moon, then like a half-moon, and at last it was restored entire.

2. A thing which on other occasions did not happen so visibly except when after several unequal revolutions, the moon returns to exactly the same point at fixed intervals; that is to say, when the moon is found in the same sign of the zodiac, exactly opposite to the rays of the sun, and stops there a few minutes, which in geometry are called parts of parts.

3. And although the changes and motions of both sun and moon, as the inquiries into intelligible causes have remarked, perpetually return to the same conjunction at the end of each lunar month, still the sun is not always eclipsed on these occasions, but only when the moon, as by a kind of balance, is in the exact centre between the sun and our sight.

4. In short, the sun is eclipsed, and his brilliancy removed from our sight, when he and the moon, which of all the constellations of heaven is the lowest, proceeding with equal pace in their orbits, are placed in conjunction in spite of the height which separates them (as Ptolemy learnedly explains it), and afterwards return to the dimensions which are called ascending or descending points of the ecliptic conjunctions: or, as the Greeks call them, defective conjunctions. And if these great lights find themselves in the neighbourhood of these points or knots, the eclipse is small.