nine
varieties may be either soft, hard, or intermediate, thus making
twenty-seven varieties. Any of these may be either smooth, harsh, or
intermediate, thus increasing the number to eighty-one. Smooth earths,
as I use the term, have congealed uniformly, harsh earths, unequally,
and intermediate earths in some intermediate manner. For this reason
soft and intermediate earths may be harsh; hard, rarely so. Finally,
since any of these may be either white, black, yellow, red, green,
blue, gray, brown, or even some other color, a vast number of varieties
are seen to exist.
Taste
increases the varieties of simple earths. They may be oily or
oily-sweet, each of which is due to a good juice and true taste. Some
are oily and acrid or at the same time astringent. Others are only
acrid or astringent.
Although
the odor of earths agrees with the taste, Latin writers do not use the
same names for both qualities but describe odors by those names
mentioned above. Earths that have been dry for a long time have an
agreeable odor when they absorb sudden and moderate rains.
Some
earths can be broken up with ease, others are glutinous or
intermediate. These qualities do not form new varieties since meager
earths can always be broken with ease, unctuous earths are glutinous,
intermediate earths, intermediate. In the same way light, heavy and
intermediate earths do not form new varieties since all porous earths
are light, dense earths, heavy, etc. Thus we see that Nature has
combined these many differences in such ways as to produce the many
species of earths mentioned by the older writers. Many species lack
names and the names of some come from either their natural color or the
region in which they are found.
I
shall now take up the forms of earths, those cultivated by farmers and
those used by potters, fullers, painters, carpenters, and other
artisans. All prefer simple earths and reject the composite ones except
the potters who use some arenaceous earths. Farmers sometimes select
unctuous sandy soils for growing sesame. They classify soils first of
all according to their fertility, sterility, or intermediate qualities
and then according to their denseness or porosity without considering
an intermediate class. Finally they consider the taste. Hard, soft, and
intermediate classes are not important since all dense earths are
usually hard and porous earths soft although any dense, porous, or
intermediate earth may be either hard, soft, or intermediate as stated
above. But this is a digression from farming.
In
cultivated fields only the upper portion is hard and this is only true
of unplowed fields before they are moistened by rains. Marl, sometimes
used by farmers, is usually hard. It does not matter to a farmer if his
soil is harsh, smooth, or intermediate and it is of no importance if it
is black, gray, yellow, red, or any other color if it suits his
purpose. There are in all twenty-one species of earths which are of
interest to the farmer, nine species of rich earths and six each of the
poor and intermediate. Rich or unctuous earths are the best since in
these, especially in the sweet varieties, there exists a juice which
nourishes the grain. Rich porous earths
