BOOK II. xni. 64-66 



of Mercury in Capricorn, of the moon in the Bull, 

 at the middle of each, and the points lowest and 

 nearest to the centre of the earth are opposite. The 

 result of this is that they appear to move slower and 

 to be smaller when they are travelHng at the highest 

 point of their circuit, but to be larger and travel 

 faster when they have come nearer to the earth, not 

 because they actually accelerate or reduce their 

 natural motions, which are fixed and individual to 

 them, but because Hnes drawn from the top of the 

 arc to the centre necessarily converge like the spokes 

 of a wheel, and the same motion at one time is 

 perceived as faster and at another slower according 

 to its distance from the centre. 



Another reason of their elevations is because they 

 have the points of their arcs highest from their 

 centre in different signs — Saturn in the 20th degree 

 of the Scales, Jupiter in the 15th of the Crab, Mars 

 in the 28th of Capricorn, the sun in the 29th of the 

 Ram, Venus in the 27th of the Fishes, Mercury in 

 the 15th of Virgo, the moon in the 4th of the BuU. 



A third explanation of their altitudes is explained 

 by the dimensions of the firmament, not that of a 

 circle, the eye judging them to rise or to sink through 

 the depth of the air. 



Linked with this is the cause of the latitudes ofOrMtsoftf. 

 the zodiac and of its obliquity. The stars we have rJiMim to 

 mentioned " travel through the zodiac, and the only thezodiac; 

 habitable part of the earth is what lies beneath it — 

 all the other parts towards the poles are frost-bound. 

 Only the planet Venus goes two degrees outside the 

 zodiac ; this is understood to be the reason that 

 causes some animals to be born even in the desert 

 places of the world. The moon also wanders through 



213 



