And the Heaven of Mars may be compared to Music because of two properties. One is its most beautiful relative position; for, when enumerating the movable Heavens, from which one soever you may begin, either from the lowest or from the highest, this Heaven of Mars is the fifth; it is the central one of all, that is, of the first, of the second, of the third, and of the fourth. The other is, that this Mars dries up and burns things, because his heat is like to that of fire; and this is why it appears flaming in colour, sometimes more and sometimes less, according to the density and rarity of the vapours which follow it, which of themselves are often kindled, as is determined in the first book on Meteors. And, therefore, Albumassar says that the kindling of these vapours signifies the death of Kings and the change of Kingdoms; for they are the effects of the dominion of Mars. And, therefore, Seneca says that, on the death of Augustus, he beheld on high a ball of fire. And in Florence, at the beginning of its destruction, there was seen in the air, in the form of a cross, a great quantity of these vapours following the planet Mars. And these two properties are in Music, which is all relative, as is seen in harmonized words and in songs, from which the sweeter harmony results in proportion as the relation is more beautiful, which in this Science is especially beautiful, because there is in it a special harmony. Again, Music attracts to itself human spirits, which are as it were chiefly vapours from the heart, so that they almost cease from all labour; so is the whole soul when it hears it, and the power of all those spirits flies as it were to the spirit of sense, which receives the sound.