Ptolemy - Ptolemy's Tetrabiblos - Ch. 7 lyrics

CHAPTER VII DIURNAL AND NOCTURNAL THE day and the night are the visible divisions of time. The day, in its heat and its aptitude for action, is masculine:--the night, in its moisture and its appropriation to rest, feminine. Hence, again, the Moon and Venus are esteemed to be nocturnal; the Sun and Jupiter, diurnal; and Mercury, common; since in his matutine position he is diurnal, but nocturnal when vespertine. Of the other two planets, Saturn and Mars, which are noxious, one is considered to be diurnal, and the other nocturnal. Neither of them, however, is allotted to that division of time with which its nature accords (as heat accords with heat), but each is disposed of on a contrary principle: and for this reason, that, although the benefit is increased when a favourable temperament receives an addition of its own nature, yet, the evil arising from a pernicious influence is much mitigated when dissimilar qualities are mingled with that influence. Hence the coldness of Saturn is allotted to the day, to counterbalance its heat; and the dryness of Mars to the night, to counterbalance its moisture. Thus each of these planets, being moderated by this combination, is placed in a condition calculated to produce a favourable temperament.