of good Sand is, that when 'tis put upon any
Thing that is White and shak'd off, it leaves no Mark behind.

The Sand which is dug out of the Earth has all these Qualities, and is
esteem'd the best. _Vitruvius_ makes four sorts of it; _viz._ White,
Black, Red, and Bright like a Carbuncle.

If it happen that there be no good Place to dig Sand in, we may make use
of Sea-Sand, or River-Sand, which is likewise better for Plastering than
the Sand which is digged, which is excellent for Building, because it
drys quickly. Gravel likewise is very good, provided the grosser Parts
be taken away. Sea-Sand is worst of all, because 'tis long adrying; and
for this Reason, where 'tis made use of in Building, they are forc'd to
desist sometimes till it dry.

The Sand which is found near _Naples_ call'd _Pozzolana_ is so proper to
make good Mortar, if it be mixed with Lime, that not only in the
ordinary Fabricks, but even in the very bottom of the Sea it grows into
a wonderful hard Body. In Old Times they made use of it for Moles or
Ports of the Sea, for after having made with Piles and Boards a
Partition, they fill'd up the whole Compass of the Partition with this
Mortar, which dry'd of it self in the middle of the Water and became a
solid Body.

ART. II.

_Of the Use of the Materials._

The first thing we should have a Care of before we begin to build, is,
to have the Stones dug out of the Quarry before they be used, and to
expose them in some open Place, to the end that those which are
endamaged by the Air, during this Time, may be put in the Foundation,
and those that prove Durable and Good may be kept for the Walls above
Ground.

We must likewise have a great care of the Wood which we make use of;
That it be cut in a seasonable Time, which is in Autumn and Winter; for
then it is not full of that superfluous Humidity which weakened it in
dilating its Fibers, but it is firm and well closed by the Cold. This is
so true, that the Wood of Trees which grow and become very great in a
little Time, by reason of their great Humidity, is tender and apt to
break, and very unfit for Building. Which Experience shows us
particularly in those Firrs call'd _Supernates_, which grow in _Italy_,
on that side the _Apennine_, towards the _Adriatick_-Sea, for they are
great and beautiful, but their Wood is not good for Building; whereas
those on the other side of the Mountain, which are exposed to Heat and
Dryness, call'd _Infernates_, are ve