Furthermore, a man may say that dryness, being mixed with heat, attenuateth and subtilizeth the spirit, and makes it pure and of an ethereal nature and consistence; for the soul itself, according to Heraclitus, is of a dry constitution; whereas moisture does not only dim the sight and dull the hearing, but when mingled with the air and touching the superficies of mirrors, dusketh the brightness of the one and takes away the light of the other. Or perhaps, on the contrary, by some refrigeration and condensation of this spirit, like the tincture and hardening of iron, this part of the soul which does prognosticate may become more intense and get a perfect edge. Just as tin being melted with brass (which of itself is rare and spongeous) does drive it nearer and make it more massy and solid, and withal causeth it to look more bright and resplendent; so I cannot see any reason, why this prophetical exhalation, having some congruence and affinity with souls, may not fill up that which is lax and empty, and drive it more close together. For there are many things which have a reference and congruity one with another; as the bean is useful in dyeing purple, and soda in dyeing saffron, if they be mixed therewith; and as Empedocles says, Linen is dyed with the bright saffron’s flower. And we have learned of you, Demetrius, that only the river Cydnus cleaneth the knife consecrated to Apollo, in the city of Tarsus in Cilicia, and that there is no other water which can scour and cleanse it. So in the town of Olympia, they temper ashes with the water of the river Alpheus, with which they make a mortar wherewith they plaster the altar there; but if this be attempted to be done by the water of any other river, it is all to no purpose.