Page:The Natural History of Pliny.djvu/74

 40 pliny's natural histoet. [Book IL CHAP. 11. (14.) — OF THE MOTION" OP THE MOON. It is certain that the moon, having lier horns always turned from the sun, when she is waxing, looks towards the east ; when she is waning, towards the west. Also, that, from the second day after the change, she adds 47|- minutes^ each day, until she is full, and again decreases at the same rate, and that she always becomes invisible when she is within 14 de- grees of the sun. This is an argument of the greater size of the planets than of the moon, since these emerge when they are at the distance of 7 degrees only^. But their altitude causes them to appear much smaller, as we observe that, during the day, the brightness of the sun prevents those bodies from being seen which are fixed in the firmament, although they shine then as well as in the night : that this is the case is proved by eclipses, and by descending into very deep wells. CHAP. 12. (15.) — OP THE MOTIONS OP THE PLANETS AND THE GENEEAL LAWS OP TEEIE ASPECTS^. The three planets, which, as we have said, are situated above the sun^, are visible when they come into conjunction with him. They rise visibly^ in the morning, when they are not more than 11 degrees from the sun^ ; they are afterwards directed by the contact of his rays-^, and when they attain the trine aspect, at the distance of 120 degrees, they take their morning stationary positions^, which are termed pri- ^ In a subsequent part of the work, xviii. 75, the author gives a dif- ferent rate of increase, viz. 51^ minutes ; neither of these nmnbers is correct ; the mean rate of increase being, according to Alexandre, about 54' or 55' ; Lemaire, ii. 261, 262. See also Marcus in Ajasson, ii. 311-14. 2 It is scarcely necessary to remark, that the effect, as here stated, has no connexion with the supposed cause. 3 " luminum canonica." * Mars, Jupiter, and Saturn. 5 They are then said, in astronomical language, to rise heHacally. ^ In the last chapter this distance was stated to be 7 degrees ; see the remarks of Alexandre, iia Lemaire, ii. 263. 7 "radiorum ejus contactu reguntur." The doctrine of the ancient astronomers was, that the motions of the planets are always governed by the rays of the sun, according to its position, attracting or repeUing them. ^ A planet appears to be stationary, i. e. to be referred to the same point of the zodiac, when it is so situated with respect to the earth, that