Archimedes Texts

32
to adorn our Work, I shall omit them, and
proceed to treat of the Method of Building as
addressing myself to Artificers approv'd for
Skill and Experience, with more Freedom
than perhaps would be allow'd by those who
are sor more exact philosophising. Cato advises
to dig the Stone in Summer, to let it lie in the
open Air, and not to use it under two Years:
In Summer, to the Intent that it may grow
accustom'd by Degrees to Wind, Rain, and
Frost, and other Inclemencies of the Weather,
which it had not felt before. For if Stone,
immediately upon its being dug out of the
Quarry, while it is full of its native Juice and
Humidity, is expos'd to severe Winds and
sudden Frosts, it will split and break to Pieces.
It should be kept in the open Air, in order to
prove the Goodness of each particular Stone,
and how well it is able to resist the Accidents
that injure it, making Experiment by this small
Trial, how long they are likely to hold against
the Assaults of Time. They should not be
used under two Years, to the Intent that you
may have Time to find out such among them
as are weak in their Nature, and likely to dam
age the Work, and to seperate them from the
good ones; for it is certain, in one and the
same Kind of Stones there is a Difference in
Goodness of any Sort of Stone, and its Fit
ness for this or that particular Situation, is best
learnt from Use and Experience; and you
may much sooner come at their Values and
Properties from old Buildings, than from the
Writings and Precepts of Philosphers. How
ever, to say something briefly of Stones in ge
neral, we will beg Leave to offer the follow
ing Observations.

ALL white Stone is softer than red, the clear
is more easily wrought than the Cloudy, and
the more like Salt it looks, the harder it is to
work. Stone that looks as if it were strew'd
over with a bright shining Sand, is harsh; if
little Sparks, as it were, of Gold are intermix'd,
it will be stubborn; if it has a Kind of little
black Points in it, it will be hard to get out
of the Quarry: That which is spotted with
angular Drops is stronger than that which has
round ones, and the smaller those Drops are,
the harder it will be; and the finer and clearer
the Colour is, the longer it will last. The
Stone that has fewest Veins, will be most
entire, and when the Veins come nearest in
Colour to the adjoining Parts of the Stone, it
will prove most equal throughout: The smaller
the Veins, the handsomer; the more winding
they run, the more untoward; and the more
knotty, the worse, Of these Veins that is
most apt to split which has in the Middle a
reddish Streak, or of the Colour of rotten
Oker. Much of the same Nature is that which
is stain'd here and there with the Colour of
faded Grass, but the most difficult of all is
such as looks like a cloudy Piece of Ice. A
Multitude of Veins shews the Stone to be de
ceitful and apt to crack; and the straiter they
are, the more unsaithful. Upon breaking a
Stone, the more fine and polish'd the Frag
ments appear, the closer bodied it is; and that
which when broken has its Outside the least
rugged, will be more manageable than those
which are rough. Of the Rough ones, those
which are whitest will be worst for working;
whereas, on the Contrary, in brown Stones,
those of the smallest and finest Grain are least
obedient to the Tool. All mean ordinary
Stones are the Harder for being spungy, and
that which being sprinkled with Water is long
est in drying, is the most crude.

ALL heavy Stones are more solid and easier
to polish than light ones, which upon rubbing
is much more apt to come off in Flakes than
such as are heavy. That which upon being
struck gives the best Sound, is closer made than
that which sounds dull; and that which upon
strong Friction smells of Sulphur, is stronger
than that which yields no Smell at all. Last
ly, that which makes the most Resistance against
the Chizzel will be most firm and rigid against
the Violence of Storms. They say, that those
Stones which hold together in the largest Scant
lings at the Mouth of the Quarry, are firmest
against the Weather. All Stone too is softer
when it is just dug up, than after it has been
some Time in the Air, and when it is wetted,
or sostened with Water, is more yielding to the
Tool than when it is dry. Also such Stones as
are dug out of the moistest Part of the Quarry,
will be the closest when they come to be dry;
and it is thought that Stones are easier wrought
in a South-wind than in a North, and are more
apt to split in a North-wind than in a South.
But if you have a Mind to make an Experi
ment how your Stone will hold out against
Time, you may judge from hence: If a Piece
of it, which you soak in Water, increases much
of its Weight, it will be apt to be rotted by
Moisture; and that which flies to Pieces in
Fire, will bear neither Sun nor Heat. Neither
do I think that we ought to omit here some
Things worthy Memorial, which the Ancients
relate of some Stones.