In the next place, we may observe that there are different kinds
of fire—(1) flame, (2) light that burns not, (3) the red heat of
the embers of fire. And there are varieties of air, as for
example, the pure aether, the opaque mist, and other nameless
forms. Water, again, is of two kinds, liquid and fusile. The
liquid is composed of small and unequal particles, the fusile of
large and uniform particles and is more solid, but nevertheless
melts at the approach of fire, and then spreads upon the earth.
When the substance cools, the fire passes into the air, which is
displaced, and forces together and condenses the liquid mass.
This process is called cooling and congealment. Of the fusile
kinds the fairest and heaviest is gold; this is hardened by
filtration through rock, and is of a bright yellow colour. A
shoot of gold which is darker and denser than the rest is called
adamant. Another kind is called copper, which is harder and yet
lighter because the interstices are larger than in gold. There is
mingled with it a fine and small portion of earth which comes out
in the form of rust. These are a few of the conjectures which
philosophy forms, when, leaving the eternal nature, she turns for
innocent recreation to consider the truths of generation.
Water which is mingled with fire is called liquid because it
rolls upon the earth, and soft because its bases give way. This
becomes more equable when separated from fire and air, and then
congeals into hail or ice, or the looser forms of hoar frost or
snow. There are other waters which are called juices and are
distilled through plants. Of these we may mention, first, wine,
which warms the soul as well as the body; secondly, oily
substances, as for example, oil or pitch; thirdly, honey, which
relaxes the contracted parts of the mouth and so produces
sweetness; fourthly, vegetable acid, which is frothy and has a
burning quality and dissolves the flesh. Of the kinds of earth,
that which is filtered through water passes into stone; the water
is broken up by the earth and escapes in the form of air—this in
turn presses upon the mass of earth, and the earth, compressed
into an indissoluble union with the remaining water, becomes
rock. Rock, when it is made up of equal particles, is fair and
transparent, but the reverse when of unequal. Earth is converted
into pottery when the watery part is suddenly drawn away; or if
moisture remains, the earth, when fused by fire, becomes, on
cooling, a stone of a black colour. When the earth is finer and
of a briny nature then two half-solid bodies are formed by
separating the water,—soda and salt. The strong compounds of
earth and water are not soluble by water, but only by fire. Earth