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, Lib. 3.
Chap. 8. 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.
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.
But the Ordinary Practice is, to Lib. 3.
Chap. 2. 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.]