Archimedes Texts

Of the Method of cutting Marble into thin Scantlings, and what Sand is best
for that Purpose; as also of the Difference and Agreement between Mosaic
Work in Relieve, and Flat, and of the Cement to be used in that Sort of Work.

As to those Incrustations which are fasten
ed on to the Work, whether flat Facings,
or pannelled Work, the same Method is to be
used in both. It is very surprizing to consider
the Diligence which the Antients used in saw
ing and polishing their Scantlings of Marble.
I myself have seen some Pieces of Marble above
six Foot long and three broad, and yet scarce
half an Inch thick, and these have been joined
together with a curve Line, that the Spectators
might not easily find out where the Junctures
were. Pliny tells us, that the Ancients com
mended the Sand of Æthiopia as the Best for
sawing of Marble, and that the Indian came up
the nearest to it: But that the Ægyptian was
rather too soft, though even that was better than
ours. They tell us that there is a Sort found
in a certain Flat in the Adriatic Sea, which
was much used by the Ancients. We dig a
Sand about the Shore of Pozzuolo, which is not
improper for this Purpose. The sharp Sand
found in any Sort of Torrent is good, but the
larger it is, the wider it cuts and the more it
eats into the Stone; whereas the softer it goes
through, the Smoother it leaves the Surface,
and the more easily to be polished. The Po
lishing must be begun with chizzelling, but
ended with the softest and smoothest rubbing.
The Theban Sand is much commended for rub
bing and polishing of Marble; so is the Whet
stone, and the Emeril, whose Dust nothing can
exceed for this Purpose. The Pumice-stone
too, for giving the last Polish, is very useful.
The Scum of calcined Tin, which we call Put
ty, white Lead burnt, the Tripoli Chalk in
particular, and the like, if they are beat in
to the finest Dust that possibly can be, still re
taining their Sharpness, are very good for this
Work. For fastening on the Scantlings, if
they are thick, fix into the Wall either Pins of
Iron, or little Spars of Marble sticking out from
the Wall, to which you may fasten your Scant
ling without any Thing of Cement. But if the
Scantlings are thin, after the second Plaister
ing, instead of Mortar, take Wax, Pitch, Ro
sin, Gum Mastic, and a good Quantity of any
other Sort of Gum whatsoever, all melted and
mixed together, and warm your Piece of Mar
ble by degrees, lest if you put it to the Fire at
once of a Sudden, the Heat should make it
crack. In fixing up your Scantlings, it will be
very laudable if the Juncture and Order in
which you place them, produce a beautiful Ef
fect, by means of the Veins and Colours an
swering and setting off one another. I am
mightily pleased with the Policy of the Anci
ents, who used to make those Parts which lay
nearest to the Eye as neat and as exactly polished
as was possible, but did not take so much Pains
about those which stood at any Distance, or
Heigth, and in some Places put them up with
out any polishing at all, where they knew the
Eye of the most curious Examiner could not
reach them. Mosaic Work in Relieve, and
that which is flat, agree in this Particular,
that both are designed to imitate Painting, by
means of an artful Composition of various Co
lours of Stones, Glass, and Shells. Nero is said
to have been the First that had Mother of
Pearl cut and mixed in Mosaic Work. But
herein they differ, that in Mosaic Work in Re
lieve we use the largest Pieces of Marble, &c.
that we can get; whereas in the flat Mosaic,
we put none but little square Pieces, no big
ger than a Bean; and the smaller these Pieces
are, the more Bright and Sparkling they make
the Work, the Light by so many different Faces
being broke into the more various Parts. They
differ too in this, that in fastening on the for
mer, Cement made of Gums is the Best; but
in the flat Work, we should use Mortar made
of Lime, with a Mixture of Tyburtine Stone,
beat as small as Dust. There are some that, in
flat Work Mosaic Work, are for steeping the
Lime often in hot Water, in order to get out
its Saltness and make it softer and more gluey.
I have known some of the hardest Stone polish
ed upon a Grind-stone, in order to be used in
the Mosaic in Relieve. In the flat Mosaic Work
you may fasten Gold to Glass with a Cement
of Lead or Litharge, which may be made more
liquid than any Sort of Glass whatsoever. All