ich is
a sphere, there is no opposition of above or below, and that which is to
us above would be below to a man standing at the antipodes. The greater
or less difficulty in detaching any element from its like is the real
cause of heaviness or of lightness. If you draw the earth into the
dissimilar air, the particles of earth cling to their native element,
and you more easily detach a small portion than a large. There would
be the same difficulty in moving any of the upper elements towards the
lower. The smooth and the rough are severally produced by the union of
evenness with compactness, and of hardness with inequality.

Pleasure and pain are the most important of the affections common to the
whole body. According to our general doctrine of sensation, parts of the
body which are easily moved readily transmit the motion to the mind; but
parts which are not easily moved have no effect upon the patient. The
bones and hair are of the latter kind, sight and hearing of the former.
Ordinary affections are neither pleasant nor painful. The impressions
of sight afford an example of these, and are neither violent nor
sudden. But sudden replenishments of the body cause pleasure, and sudden
disturbances, as for example cuttings and burnings, have the opposite
effect.

>From sensations common to the whole body, we proceed to those of
particular parts. The affections of the tongue appear to be caused by
contraction and dilation, but they have more of roughness or smoothness
than is found in other affections. Earthy particles, entering into the
small veins of the tongue which reach to the heart, when they melt into
and dry up the little veins are astringent if they are rough; or if
not so rough, they are only harsh, and if excessively abstergent, like
potash and soda, bitter. Purgatives of a weaker sort are called salt
and, having no bitterness, are rather agreeable. Inflammatory bodies,
which by their lightness are carried up into the head, cutting all that
comes in their way, are termed pungent. But when these are refined by
putrefaction, and enter the narrow veins of the tongue, and meet there
particles of earth and air, two kinds of globules are formed--one of
earthy and impure liquid, which boils and ferments, the other of pure
and transparent water, which are called bubbles; of all these affections
the cause is termed acid. When, on the other hand, the composition of
the deliquescent particles is congenial to the tongue, and