two; then laying it on, it must be thoroughly pounded by a number of men with wooden 
rammers, till it be compact, and the thicknes be three quarters (of a foot): upon this is laid 
the nucleus, composed of three parts of testaceous matter mixed with one part of lime, so 
that the thicknes of the pavement may not be less than six inches. Over the nucleus the 
paving pieces, whether sectiliae or tesserae, are to be exactly laid with rule and level: when 
these are laid, and have a proper declination, they must be so rubbed, that, if they be sedtilig. 
no risings may remain, whether they be oval (in scutulis), triangular, square, or hexangular. 
but the whole composition must be perfectly smooth: if they be tesserae, all the angles should 
be equal, and none rise from the surface; for if the angles are not all equal and level, the 
surface will not be so smooth as it ought: the pointed tiburtine tiles are much desired, because 
they have no hollows or protuberances, but are rubbed flat and straight upon the rubbed sur¬ 
face; when it is to be levigated and polished, marble powder is sifted, and over that is laid 
a coat of lime and sand. 
(3*) The word testa in the text may signisy the matter 
of any burnt clays, as bricks, tiles, &c.: it is so used by 
Vitruvius in several other passages, as testaceum pavimen¬ 
tum, in chapter 4. following. 
Perrault has erroneously written two parts of this testa is 
to be used to one part of lime, whereas the text expresses 
three parts to one. 
(4*) L. 7. ch. 1. sive sectilibus, seu tesseris—wbetbe 
sestilia or tesserae. -Of these two kinds of pavements Perrault 
and Galiani agree that the tesserae is the Mosaic kind, 
formed by very small cubical pieces, because tesserae was 
one name usually given to the small cubical bodies called 
dice. Philander on the contrary thinks the sectiliae were the 
Mosaic pavements, to which opinion I also incline; for 
although the word tesserae was used as one of the names ol 
dice, vet it also signified a square, or any square body, and 
may therefore have signified a square paving stone, either 
large or small, a cube appearing a square when laid in 
the pavement; but it probably signified a large sort of 
stone, for the following reasons. Vitruvius in this 
chapter says, that in the tesserae pavements it is necessary 
to work all the angles of the stones exactly equal of 
alike— teseris strustum erit ut ex omnes angulos habeant 
equales, which is indeed necessary in large stones, in ordei 
that they may be regularly laid, but not in the minute 
pieces of which the Mosaic pavements consisted; becaule 
their own figure was not intended to be conspicuous, they 
being only used as the constituent particles of other forms; 
and the examples of the antient Mosaic that have come to 
O K 
our knowledge prove that such exactness was not pfac- 
tised in those minute pieces. Again, Vitruvius hereafter 
mentions large tesseræ two inches in thickness, which plainly 
proves that tesseræ sometimes at least signisied large 
stones; for stones must be considerably large to require 
to be two inches in thickness. Vitruvius directs the 
sectilia pavements to be rubbed smooth after they are 
laid, but he does not direct the tesserae to be so rubbed, 
which is an implication that these latter were large stones, 
that might be so previously wrought and laid as not to 
require rubbing afterward ; but it would be very difficult 
or scarce possible to lay the very minute pieces of the 
Mosaic pavements in a sensibly perfect plane, and 
therefore they would require rubbing after they were 
The example Vitruvius mentions of the tiburtine tiles 
(which, by their being described to have no hollows or 
protuberances, we may infer were not very small) follow¬ 
ing immediately after the mention of the tesserae, is a 
farther support to the opinion that the latter likewise were 
not of the small kind ; large tesseræ two inches on the 
edge are also hereafter mentioned: this at least proves that 
all of the tesserae kind could not be so small as the stones 
used in the Mosaic pavements, which were sometimes lels 
than half an inch, and seldom more than one inch cube; 
but as these are faid to be two inches thick, it implies 
that their surface was much larger: for these realons, 
therefore, I am of opinion that the sectillie were the kind 
now commonly knowii by the term Mosaic, or rather 
Musaic, as Vitruvius writes the word.