maketh great noise and sound, if it be strongly blown, and afterward
violently broken. And with the thunder cometh lightning, but lightning
is sooner seen, for it is clear and bright; and thunder cometh later
to our ears, for the wit of sight is more subtle than the wit of
hearing. As a man seeth sooner the stroke of a man that heweth a tree,
than he heareth the noise of the stroke.

The lightning which is called Clarum is of a wonderful kind, for it
catcheth and draweth up wine out of the tuns, and toucheth not the
vessel, and melteth gold and silver in purses, and melteth not the
purse.

As wits and virtues are needed to the ruling of kind, so to the
perfection thereof needeth needly some spirits, by whose benefit and
continual moving, both wits and virtues in beasts are ruled to work
and do their deeds. As we speak here of a spirit, a spirit is called a
certain substance, subtle and airy, that stirreth and exciteth the
virtues of the body to their doings and works. A spirit is a subtle
body, by the strength of heat gendered, and in man's body giving life
by the veins of the body, and by the veins and pulses giveth to
beasts, breath, life, and pulses, and working, wilful moving, and wit
by means of sinews and muscles in bodies that have souls. Physicians
say that this spirit is gendered in this manner wise. Whiles by heat
working in the blood, in the liver is caused strong boiling and
seething, and thereof cometh a smoke, the which is pured, and made
subtle of the veins of the liver. And turneth into a subtle spiritual
substance and airly kind, and that is called the natural spirit. For
kindly by the might thereof it maketh the blood subtle. And by
lightness thereof it moveth the blood and sendeth it about into all
the limbs. And this same spirit turneth to heartward by certain veins.