BOOK XVIII. Lviii. 218-UX. 222 



' rising ', and the former as their ' occultation ' rather 

 than ' setting ') ; or bv means of the following mode 

 — bv the dav on which the risings and settings of the 

 stars begin or cease to be visible at the rising or 

 setting of the sun, these being designated their 

 morning or evening risings and settings according as 

 each of them occurs at dawn or at dusk. Thev re- 

 quire intervals of at least three-quarters of an hour 

 before sunrise or after sunset in order to be visible. 

 Moreover there are some stars that rise and set 

 twice " ; and all that is said here refers to the stars 

 which we have stated to be fixed stars. 11. 7 ff. 



LIX. The divisions of the seasons are fixed by the •so'»'" 

 fourfold distribution of the year corresponding with 

 the increascs and decreases of dayliglit. From mid- 

 winter onward this increases in length, and in 90 days 

 3 hours at the spring equinox the dav becomes equal 

 to tlie night. From then to the summer solstice, a 

 period of 94: days 12 hours, th(? day is longer than 

 the night . . . until the autunm equinox, and then 

 the night having become equal to the day goes on 

 increasing from that point until midwinter, a period 

 of 88 days 3 hours (in the present passage the term 

 ' hours ' in each addition and subtraction denotes equi- 

 noctial hours and not the hours of any day in particular *) 

 and all these changes occur at the eighth degree of the 

 signs of the zodiac, midwinter at the eighth dcgree of 

 Capricorn, about Dccember 26, the equinox at the 

 eighth of the Ram, the summer solstice at the eighth 

 of the Crab and the other equinox at the eighth of 

 the Scales — which days themselves also usually give 

 some indications of changes of weather. Again these 



and night together only at the equinoxes, and at other periods 

 WU8 longer by day and shorter by night, or vice versa. 



329 



