Besides, the bodies of the animated beings which move in the heaven may
be of different degrees of heat; none of them is cold, as is witnessed
to by their location. The planet named Jupiter is a suitable mixture of
fire; likewise with Venus. That is why they seem to move harmoniously.
As to the fiery planet Mars, it contributes its share to the mixture
(of the general action of the stars). As to Saturn, its case is
different, because of its distance. Mercury is indifferent, because it
assimilates itself easily to all.