7. Of Diurnal and Nocturnal Planets.

Similarly, since of the two most obvious intervals of those which make up time, the day is more masculine because of its heat and active force, and night more feminine because of its moisture and its gift of rest, the tradition has consequently been handed down that the moon and Venus are nocturnal, the sun and Jupiter diurnal, and Mercury common as before, diurnal when it is a morning star and nocturnal as an evening star. They also assigned to each of the sects the two destructive stars, not however in this instance on the principle of similar natures, but of just the opposite; for when stars of the same kind are joined with those of the good temperament their beneficial influence - is increased, but if dissimilar stars are associated with the destructive Ones the greatest part of their injurious power is broken. Thus they assigned, Saturn, which is cold, to the warmth of day, and Mars, which is dry, to the moisture of night, for in this way each of them - attains good proportion through admixture and becomes a proper member of its sect, which provides moderation.

Ptolemy's Tetrabiblos

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