TIMAEU [25]
nature, which
differs from all juices, having a burning quality which dissolves
the flesh; it is called opos (a vegetable acid).
As to the kinds of earth, that which is filtered through water
passes into stone in the following manner:-The water which mixes
with the earth and is broken up in the process changes into air, and
taking this form mounts into its own place. But as there is no
surrounding vacuum it thrusts away the neighbouring air, and this
being rendered heavy, and, when it is displaced, having been poured
around the mass of earth, forcibly compresses it and drives it into
the vacant space whence the new air had come up; and the earth when
compressed by the air into an indissoluble union with water becomes
rock. The fairer sort is that which is made up of equal and similar
parts and is transparent; that which has the opposite qualities is
inferior. But when all the watery part is suddenly drawn out by
fire, a more brittle substance is formed, to which we give the name of
pottery. Sometimes also moisture may remain, and the earth which has
been fused by fire becomes, when cool, a certain stone of a black
colour. A like separation of the water which had been copiously
mingled with them may occur in two substances composed of finer
particles of earth and of a briny nature; out of either of them a half
solid body is then formed, soluble in water-the one, soda, which is
used for purging away oil and earth, and other, salt, which harmonizes
so well in combinations pleasing to the palate, and is, as the law
testifies, a substance dear to the gods. The compounds of earth and
water are not soluble by water, but by fire only, and for this
reason:-Neither fire nor air melt masses of earth; for their
particles, being smaller than the interstices in its structure, have
plenty of room to move without forcing their way, and so they leave
the earth unmelted and undissolved; but particles of water, which
are larger, force a passage, and dissolve and melt the earth.
Wherefore earth when not consolidated by force is dissolved by water
only; when consolidated, by nothing but fire; for this is the only
body which can find an entrance. The cohesion of water again, when
very strong, is dissolved by fire only-when weaker, then either by air
or fire-the former entering the interstices, and the latter
penetrating even the triangles. But nothing can dissolve air, when
strongly condensed, which does not reach the elements or triangles; or
if not strongly condensed, then only fire can dissolve it. As to
bodies composed of earth and water, while the water occupies the
vacant interstices of the earth in them which are compressed by force,
the particles of water which approach them from without, finding no
entrance, flow around the entire mass and leave it undissolved; but
the particles of fire, entering into the interstices of the water,
do to the water what water does to earth and fire to air, and are
the sole causes of the compound body of earth and water liquefying and
becoming fluid. Now these bodies are of two kinds; some of them,
such as glass and the fusible sort of stones, have less water than
they have earth; on the other hand, substances of the nature of wax
and incense have more of water entering into their composition.
I have thus shown the various classes of bodies as they are
diversified by their forms and combinations and changes into one
another, and now I must endeavour to set forth their affections and
the causes of them. In the first place, the bodies which I have been
describing are necessarily objects of sense. But we have not yet
considered the origin of flesh, or what belongs to flesh, or of that
part of the soul which is mortal. And these things cannot be
adequately explained without also explaining the affections which
are concerned with sensation, nor the latter without the former: and
yet to explain them together is hardly possible; for which reason we
must assume first one or the other and afterwards
differs from all juices, having a burning quality which dissolves
the flesh; it is called opos (a vegetable acid).
As to the kinds of earth, that which is filtered through water
passes into stone in the following manner:-The water which mixes
with the earth and is broken up in the process changes into air, and
taking this form mounts into its own place. But as there is no
surrounding vacuum it thrusts away the neighbouring air, and this
being rendered heavy, and, when it is displaced, having been poured
around the mass of earth, forcibly compresses it and drives it into
the vacant space whence the new air had come up; and the earth when
compressed by the air into an indissoluble union with water becomes
rock. The fairer sort is that which is made up of equal and similar
parts and is transparent; that which has the opposite qualities is
inferior. But when all the watery part is suddenly drawn out by
fire, a more brittle substance is formed, to which we give the name of
pottery. Sometimes also moisture may remain, and the earth which has
been fused by fire becomes, when cool, a certain stone of a black
colour. A like separation of the water which had been copiously
mingled with them may occur in two substances composed of finer
particles of earth and of a briny nature; out of either of them a half
solid body is then formed, soluble in water-the one, soda, which is
used for purging away oil and earth, and other, salt, which harmonizes
so well in combinations pleasing to the palate, and is, as the law
testifies, a substance dear to the gods. The compounds of earth and
water are not soluble by water, but by fire only, and for this
reason:-Neither fire nor air melt masses of earth; for their
particles, being smaller than the interstices in its structure, have
plenty of room to move without forcing their way, and so they leave
the earth unmelted and undissolved; but particles of water, which
are larger, force a passage, and dissolve and melt the earth.
Wherefore earth when not consolidated by force is dissolved by water
only; when consolidated, by nothing but fire; for this is the only
body which can find an entrance. The cohesion of water again, when
very strong, is dissolved by fire only-when weaker, then either by air
or fire-the former entering the interstices, and the latter
penetrating even the triangles. But nothing can dissolve air, when
strongly condensed, which does not reach the elements or triangles; or
if not strongly condensed, then only fire can dissolve it. As to
bodies composed of earth and water, while the water occupies the
vacant interstices of the earth in them which are compressed by force,
the particles of water which approach them from without, finding no
entrance, flow around the entire mass and leave it undissolved; but
the particles of fire, entering into the interstices of the water,
do to the water what water does to earth and fire to air, and are
the sole causes of the compound body of earth and water liquefying and
becoming fluid. Now these bodies are of two kinds; some of them,
such as glass and the fusible sort of stones, have less water than
they have earth; on the other hand, substances of the nature of wax
and incense have more of water entering into their composition.
I have thus shown the various classes of bodies as they are
diversified by their forms and combinations and changes into one
another, and now I must endeavour to set forth their affections and
the causes of them. In the first place, the bodies which I have been
describing are necessarily objects of sense. But we have not yet
considered the origin of flesh, or what belongs to flesh, or of that
part of the soul which is mortal. And these things cannot be
adequately explained without also explaining the affections which
are concerned with sensation, nor the latter without the former: and
yet to explain them together is hardly possible; for which reason we
must assume first one or the other and afterwards