_Vitruvius_ hath not spoke of the _Compound Order_, as of an _Order_ distinct from the _Corinthian_, the _Ionick_ and the _Dorick_; He only tells us, that sometimes upon the _Corinthian Pillar_ was placed a _Capital_ composed of several parts, which were taken from the _Corinthian_, the _Ionick_ and _Dorick Orders_. But a Consequence may be drawn from thence, that the _Order_ at present called the _Compound_, might have been in use in the time of _Vitruvius_, although they then did not make a distinct _Order_ of it; Since that, our _Compound Order_ is not essentially different from the _Corinthian_, but by its _Capital_; and so one may say, that this sole difference of the _Capital_ ought to make it a distinct _Order_ from the _Corinthian_, since according to _Vitruvius_, the _Corinthian Capital_ alone, made the _Corinthian Order_. The parts that our _Compound Order_ borrow from the _Corinthian Order_, are the _Abacus_, and the two Ranks of the Leaves of _Branch-Ursin_, which it has retained, although the _Corinthian_ have quitted them for the Leaves of the _Olive_. The other part that it takes from the _Ionick_, are the _Volutes_; which it forms in some manner according to the Model of the _Volutes_ of the _Corinthian Order_, in bending them even as the _Abacus_; for they are direct upon the _Ionick Capital_, as well as the _Abacus_. The _Echine_, or Quarter Round, which it has under the _Abacus_, it borrows rather from the _Dorick Order_, than from the _Ionick_; because this _Echine_ is immediately under the _Abacus_, as it is in the _Dorick Order_, which is not in the _Ionick_, which between the _Echine_ and the _Abacus_, places the _Channel_ which makes the _Volute_; it may notwithstanding be said, that it imitates the _Echine_ of the _Ionick Order_, in that it is cut with _Oves_ or _Eggs_, which is rarely found in the _Dorick Capital_, but are always in the _Ionick_. AN ABRIDGMENT OF THE TEN BOOKS OF ARCHITECTURE. PART II. _Containing the Architecture peculiar to the Ancients._ CHAP. I. _Of Publick Buildings._ ARTICLE I. _Of Fortresses._ [Sidenote: _Lib._ 1. _Cap._ 3.] Buildings are either _Publick_, or _Private_; Those that are Publick, appertain either to Security, or Religion, or Publick Convenience. The Fortifications of Cities are for _Security_, the Temples for _Religion_, the Market-places, Town-Houses, Theatres, Academies are for the _Publick Convenience_. The Disposition and Figures of the Ramparts were so ordered, that the Towers advanced out of the Walls to the end, that when the Enemy approached them, the Besieged which were in the Towers, might fall upon their Flank, both on the Right and the Left.