ounded 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.

ART. III.

_Of the Five Orders of Architecture_.

The Five Orders of Architecture are, the _Thuscan_, the _Dorick_, the
_Ionick_, the _Corinthian_, and the _Compound_.

These Orders were Invented to satisfie the Design that might be had of
making Fabricks more or less Massy, and more or less adorn'd, for the
Distinction of these Orders consists in two things, that as the
_Thuscan_ and _Dorick_ Order are more massy and less adorn'd, so the
_Corinthian_ and _Compound_ are Slenderer and Richer, the _Ionick_ holds
the Middle, as well in its Proportions, as its Ornaments, being less
massy and more adorn'd than the _Thuscan_ and the _Dorick_, and more
massy and less adorn'd than the _Compound_ and the _Corinthian_.

[Sidenote: _Lib. 4. Chap. 1. Praef. 4.]

[Sidenote: Lib. 4. Chap. 7._]

Though _Vitruvius_ hath only divided Architecture into Three Orders;
_viz._ The _Dorick_, the _Ionick_ and the _Corinthian_; he doth not for
all that forget to give the Proportions of the _Thuscan_, and speak of
the _Compound_.

ART. IV.

_Of Things that are Common to several Orders._

Before we treat of the Differences of these Five Orders, it would be
proper to speak of those Things that are common to several Orders; as
are the _Steps_, _Pedestals_, the _Diminution of Pillars_, their
_Channelling_, _Piedements_, _Cornices_, and _Acroteres_.

[Sidenote: _Lib. 3. Chap. 3._]

The _Steps_ which are before the Temple, ought always to be of an
unequal Number, to the end, that having put the right Foot in mounting
the first _Step_, it may likewise be upon the last.

They ought not to be more than 6 Inches 10 Lines high, nor less than 6
Inches.

[Sidenote: _Lib. 9. Chap. 2._]

Their breadth ought to be proportion'd to their height, and this
Proportion ought to be of 3 to 4; so that if the _Steps_ be 6 parts
high, which is 3 times 2, they must be 8 broad, which is 4 times 2;
following the Proportion of a Triangular Rectangle invented by
_Pythagoras_.

[Sidenote: _Lib. 3. Chap. 3._]

The Landing-places ought not to be narrower than 16 Inches and an half,
nor broader than 22 Inches, and all the _Steps_ that are round about a
Fabrick should be all of t