[363] “Venus [ambitum epicycli peragit] anno Persico 1, mensibus 7, et diebus prope 9,” that is, the period of Venus on her epicycle is 365 + 210 + 9 = 584 days nearly, according to Alfraganus. The modern mean value is also 584 days.

[364] See Lubin’s Dante e gli Astronomi Italiani. The period of 225 days may be easily deduced from Ptolemy’s system, for it is the time in which the epicycle of Venus would make an absolute revolution round its centre, the diameter becoming parallel to its former position. But the Greeks invariably reckoned the period as the time in which it revolved relatively to Earth, that is 584 days.

[365] Ep. viii. 158, 159.

[366]

“The while, little by little, as I thought, The sun ceased, and the stars began to gather.” V. N. xxiii. 176, 177. (Rossetti).

See also the prose description just before, lines 35-37.

[367] Par. xxix. 97-102.

[368] Par. xxvii. 35, 36.

[369] Par. xxv. 118-121.

[370] Qu. xx. 3-5, 26-29.