[212] I may refer to the remarks of Marcus on the respective distances from the sun at which Venus and Mercury become stationary, and when they attain their greatest elongations; Ajasson, ii. 328, 329. According to Ptolemy, Magn. Constr. lib. viii. cap. 7, the evening setting of Venus is at 5° 40′ from the sun, and that of Mercury at 11° 30′. [213] “Ἁψὶς, ligneus rotæ circulus, ab ἅπτω necto;” Hederic _in loco_. The term is employed in a somewhat different sense by the modern astronomers, to signify the point in the orbit of a planet, when it is either at the greatest or the least distance from the earth, or the body about which it revolves; the former being termed the apogee, aphelion, or the higher apsis; the latter the perigee, perhelion, or lower apsis; Jennings on the Globes, pp. 64, 65. [214] “mundo.” [215] “ratione circini semper indubitata.” [216] In consequence of the precession of the equinoxes these points are continually advancing from W. to E., and are now about 30 degrees from the situation they were in when the observations were first made by the modern astronomers. [217] Our author here probably refers to the motions of the planets through their epicycles or secondary circles, the centres of which were supposed to be in the peripheries of the primary circles. See Alexandre in Lemaire, ii. 270. [218] It is to this visible appearance of convexity in the heavens that Ovid refers in the story of Phaëton, where he is describing the daily path of the sun; Metam. ii. 63-67. [219] “quam quod illi subjacet;” under this designation the author obviously meant to include the temperate zones, although it technically applies only to the part between the tropics. It is scarcely necessary to remark, that modern discoveries have shown that this opinion respecting the Arctic zone is not strictly correct. [220] The breadth of the zodiac, which was limited by the ancients to 12 degrees, has been extended by the modern astronomers to 18, and would require to be much farther extended to include the newly discovered planet. Herschel’s Astronomy, § 254. [221] There is considerable difficulty in ascertaining the meaning of the terms employed by our author in describing the course of the planet Mercury through the zodiac; “medio ejus,” “supra,” and “infra.” Hardouin’s comment is as follows: “Duas zodiaci partes seu gradus pererrat, quum ipse per medium incedit signiferum: supra, quum deflectit ad Aquilonem, per quatuor alias ejusdem partes vagatur: infra, quum descendit ad Austrum, discedit duabus.” Lemaire, ii. 271, 272. But Marcus has shown that the opinion of Hardouin is inadmissible and inconsistent with the facts; Ajasson, ii. 338-341. He proposes one, which he conceives to be more correct, but we may probably be led to the conclusion, that the imperfect knowledge and incorrect opinions of our author on these subjects must render it impossible to afford an adequate explanation.