OF THE ELEMENTS OF
moderate ones, Tetradori, four spans ; the smallest, called
by Vitruvius Didori, by Pliny more fitly Lydii, two spans,
fit for private houses ; which the Romans likewise made use
os, and which are in length a foot and an half, or cubit, and
a foot broad.
Sand is of three kinds; pit sand, river sand, and sea sand : pit
sand is the belt; but os this the white is inferior both to
the blackisti and red sort: the * Carbuncle is superior to all.
Among these should be mentioned the earth of J Pozzuoli,
which immediately hardens in the water, and becomes stone.
Of the river sand, that is the best which is sound in torrents.
Sea sand is of the least value ; but if cleared from the saline
particles, by washing, is of use in the plaistering or rough cast-
ing of walls.
Lime is made of stone calcined; but that from the pu-
mice Hone, shells, and river pebble, does for plaistering walls.
The best stone for burning to lime is that which is white,
very hard and dense, and which loses a third of its weight in
the kiln. It must remain there sixty hours at least. Cement
is composed from one part of lime, with three parts of pit
sand, or two parts os river or sea sand.
Metal has various names and uses: I. Iron for nails, hinges,
handles, chains, &c. 2. Lead for soldering pipes and roofs.
The ancients made these things mostly of 3. copper; or 4.
brass ; 5. of copper, brass and lead; bronze was made in
imitation of Corinthian brass. This composition was usu-
ally employed for the bases of pillars, and their capitals ;
likewise for doors and statues. But of these things enough ;
seeing the Architect, particularly the Inventor of the plan,
has little concern in these matters.
* A sort of earth dug out of the mountains in Hetruria, hardened by the
stibterraneous vapours of those hills : Pliny and Vitruvius call it C'arbunculus.
Vitruv. II. 4. Pliny XVII. 4.
p Pozzuoli, anciently Puteoli, a city near Naples, famous for its Mole made,
ef this earth. See Addison’s Travels, Remarks on Italy, &c,