_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 the whole, according to the measure of any Part. For as in Humane Bodies there is a Relation between the Foot, Hand, Finger and other Parts; so amongst Works that are Perfect, from any particular Part, we may make a certain Judgment of the Greatness of the whole Work: For Example, the Diameter of a Pillar, or the Length of a _Triglyph_, creates in us a right Judgment of the Greatness of the whole Temple. And here we must remark, that to express the Relation that many things have one to another, as to their Greatness or different Number of Parts, _Vitruvius_ indifferently makes use of three words, which are _Proportion_, _Eurythmy_ and _Symmetry_. But we have thought it proper only to make use of the word Proportion, because _Eurythmy_ is a Greek word, which signifies nothing else but Proportion; and Symmetry, although a word commonly used, does not signifie in the Vulgar Languages what _Vitruvius_ understands by Proportion; for he understands by Proportion, a Relation according to Reason; and Symmetry, in the vulgar Languages, signifies only, a Relation of Parity and Equality. For the word _Simmetria_ signifies in Latin and Greek _Relation_ only. As for Example, as the Relation that Windows of Eight Foot high, have with other Windows of Six Foot, when the one are Four Foot broad, and the other Three: and Symmetry, in the Vulgar Languages, signifies the Relation, for Example, That Windows have one to another, when they are all of an equal height and equal breadth; and that their Number and Distances are equal to the Right and the Left; so that if the distances be unequal of one side, the like inequality is to be found in the other.