disposes the
parts according to their nature, this remedial power in them is called
sweet.

Smells are not divided into kinds; all of them are transitional, and
arise out of the decomposition of one element into another, for the
simple air or water is without smell. They are vapours or mists, thinner
than water and thicker than air: and hence in drawing in the breath,
when there is an obstruction, the air passes, but there is no smell.
They have no names, but are distinguished as pleasant and unpleasant,
and their influence extends over the whole region from the head to the
navel.

Hearing is the effect of a stroke which is transmitted through the ears
by means of the air, brain, and blood to the soul, beginning at the head
and extending to the liver. The sound which moves swiftly is acute; that
which moves slowly is grave; that which is uniform is smooth, and the
opposite is harsh. Loudness depends on the quantity of the sound. Of the
harmony of sounds I will hereafter speak.

Colours are flames which emanate from all bodies, having particles
corresponding to the sense of sight. Some of the particles are less and
some larger, and some are equal to the parts of the sight. The equal
particles appear transparent; the larger contract, and the lesser dilate
the sight. White is produced by the dilation, black by the contraction,
of the particles of sight. There is also a swifter motion of another
sort of fire which forces a way through the passages of the eyes, and
elicits from them a union of fire and water which we call tears.
The inner fire flashes forth, and the outer finds a way in and is
extinguished in the moisture, and all sorts of colours are generated
by the mixture. This affection is termed by us dazzling, and the object
which produces it is called bright. There is yet another sort of
fire which mingles with the moisture of the eye without flashing, and
produces a colour like blood--to this we give the name of red. A bright
element mingling with red and white produces a colour which we call
auburn. The law of proportion, however, according to which compound
colours are formed, cannot be determined scientifically or even
probably. Red, when mingled with black and white, gives a purple hue,
which becomes umber when the colours are burnt and there is a larger
admixture of black. Flame-colour is a mixture of auburn and dun; dun of
white and black; yellow of white and auburn. White and bright meeting,
and falling u