_Of the Five sorts of Fabricks_.
There are Five sorts of Fabricks; The First is called _Pycnostyle_, viz.
where the Pillars are very close one to another, in such a Proportion
that there is but from one Pillar to another, the space of a Diameter
and half of the Pillar. See the _Fig._ AA. _Tab._ 2.
The Second is called _Systile_, viz. where the Pillars seem to be joyned
together, are notwithstanding a little more distant one from another
than in the _Pycnostile_; for the intercolumniation is two Diameters of
the Pillars.
[Sidenote: _Lib. 2. Chap. 3._]
The Defect that is observ'd in the _Systile_ as well as in the
_Pycnostile_ is, that the Entrance of the Fabricks which are placed in
that distance are very narrow: So that _Vitruvius_ remarks that the
Ladies as they walk to the Temple hand in hand, were forced when they
came thither to quit one another, because they could not go two a Breast
between the Pillars. See the Figure BB. Tab. II.
The Third is called _Diastyle_; _viz._ where the Pillars are further
distant, the space of the Intercolumniation being three Diameters, and
the Inconvenience is, that the space is so great, that the _Architraves_
which lie upon the two Pillars are in danger of breaking; because the
Ancients made them of one Stone. See Figure CC. Tab. II.
[Sidenote: _Lib. 3. Chap. 8._]
The Fourth is called _Areostyle_; _viz._ where the Pillars are set very
thin, there is no certain Proportion, but the distance of one Pillar
from another, is much greater than that of _Diastyle_; and for this
reason it can have no _Architrave_ but of Wood. See the Figure DD. Tab.
II.
The Fifth is called _Eustyle_; _viz._ where the Pillars are distant from
one another by a more convenient Proportion than in any of the other
kind. The distance consists of two Diameters of the Pillars, and one
Fourth part of the Diameter: It has also this in particular, That the
Intercolumniation in the middle is larger than the rest, having three
Diameters of the Pillars; for this reason it surpasseth all others in
Beauty, Solidity, and Convenience. See Tab. III.
Although the Essentials of these five Kinds, consist in the Proportion
that is between the Diameter of the Pillar, and its Intercolumniation,
they are also different by the Proportion which is between the Diameter
of the Pillar and its height for the _Genders_ or sorts, in which the
Pillars are close one to another, ought to have the lesser Pillars; and
in that kind, where the Pillars are in a greater distance one from
another, they ought to be greater.
[Sidenote: _Lib._ 4. _Cap._ 7.]
But it's true, notwithstanding that these Proportions are not always
observ'd, and that very often, to the _Ionick_ and _Corinthian_ Pillars,
which are the smallest of all, Intercolumniations are given, which are
proper to those of the _Thuscan Order_, where the Pillars are the
greatest.
[Sidenote: _Lib. 3. Chap. 2._]
But the Ordinary Practice is, to give to the Pillars of the _Areostyle_
kind, the Magnitude of the 8th part of their height.
As to the _Diastyle_ and _Eustyle_, the height is divided into Eight
parts and an half, to give one to the breadth.
In the _Systyle_ Kind, the Height is divided into Nine parts and an
half, and one is given to the thickness.
In the _Picnostyle_, the thickness of the Pillar is the 10th part of the
height, the reason of these different Proportions is founded upon this,
that these Pillars do seem to lose of their thickness according as they
are in Proportion great or long; and it's likewise for this Reason, that
it is thought convenient to have the Pillars in the Corners thicker by a
50th part. See Tab. II. and Tab. III.