nes of War,
which were strung with strings made of Guts, whose sound they were to
observe, that they might judge of the strength and stiffness of the
Beams which were bended with those Strings. _Musick_ was also necessary
in those days for the placing musically Vessels of Brass in the
Theatres, as we have said before.

ART. III.

_What are the Parts of Architecture._

There are Three Things which ought to meet in every Fabrick, _viz._
_Solidity_, _Convenience_ and _Beauty_, which Architecture gives them;
by the due ordering and disposition of all the Parts that compose the
Edifice, and which she rules by a just Proportion, having regard to a
true _Decorum_, and well regulated _Oeconomy_; from whence it follows,
that Architecture has Eight Parts, _viz._ _Solidity_, _Convenience_,
_Beauty_, _Order_, _Disposition_, _Decorum_, _Oeconomy_.

_Solidity_ depends upon the goodness of the Foundation, choice of
Materials, and the right use of them; which ought to be with a due
order, disposition and convenient Proportion of all Parts together, and
of one in respect of another.

_Convenience_ likewise consists in the ordering and disposition, which
is so good that nothing hinders the use of any part of the Edifice.

_Beauty_ consists in the excellent and agreeable form, and the just
proportion of all its parts.

_Order_ is that which makes, that all the parts of an Edifice have a
convenient bigness, whether we consider them apart or with Relation to
the whole.

_Disposition_ is the orderly Ranging and agreeable Union of all the
parts that compose the Work; so that as Order respects the Greatness,
Disposition respects Form and Situation, which are Two Things compriz'd
under the word _Quality_, which _Vitruvius_ attributes to Disposition,
and opposes to Quantity, which appertains to Order. There are three ways
by which the Architect may take a view beforehand of the Fabrick he is
to build, _viz._ First, _Ichnography_, which is the _Geometrical_ Plan;
_Orthography_, which is the _Geometrical Elevation_, and _Scenography_,
which is _Perspective Elevation_.

_Proportion_, which is also call'd _Eurythmy_, is that which makes the
Union of all parts of the Work, and which renders the Prospect
agreeable, when the Height answers the Breadth, and the Breadth the
Length; every one having its just measure. It is defin'd, the Relation
that all the Work has with its Parts, and which every one of them has
separately to the Idea of