Glass, as a building material, was little if at all known to the ancients, and its introduction alone has been pro ductive of comforts and elegancics to which the most re fined of the Greeks and Romans were utter strangers. Their oiled paper, transparent horn, talc, shells, and linen, would now, even to an English peasant, appear a miserable expedient. An account of the application of glass in architectural works, will frequently occur as we proceed through the several branches ; but being also ex tensively employed in purposes totally distinct from what is connected with buildings, we must, for a general and full investigation of it, refer to the word GLASS.
Besides the materials which have already been enume rated as composing the principal members, as walls, roofs, floors, doors, windows, chimnies, stairs, and pavements ; hair is also necessary in the composition of mortar for plastering the surface of the walls and ceilings ; likewise various paints and papers for covering them and other parts of the work ; but as these will be described, and the modes of applying them explained in their proper places, it would be improper to swell this article by en tering upon the subject at present.
Definitions relating to the Orders.
The moderns have applied the term order to those ar chitectural forms with which the Greeks composed the facades of their temples. The principal members of an order are, I. A platform; '2. Perpendicular supports; and, 3. A lintelling or covering connecting the tops of these supports, and crowning the edifice. The proportioning these parts to the edifice and to each other, and adapt ing characteristical decorations, constitutes an order, canon, or rule. We have already seen that the Egyp tians employed all the principal members of an order, and also in some instances adapted very fine decorations, but they never varied the general character,---It continued uniformly to express dignified gravity. The Greeks, in the spirit of freedom, and with peculiar facility of inven tion, varied the expressions of their architecture as well as sculpture, and produced three species, which are de nominated orders. The principal member of an order, rs the perpendicular support or column. The accompani ments being subservient to this leading feature, the bot tom of the column is placed either on a general artificial platform, or each upon a particular plinth, or both. The lower part of the column, which rests upon the square plinth, is sometimes encompassed with mouldings, which, in allusion to their position, are, in conjunction with the plinth, termed a Base. The top part of the column is
also covered with a square plinth, with its sides straight or curved, and generally accompanied by circular mould ings or sculptured decorations upon the top part of the column which is immmediately underneath it : this, taken together, is called the Capital. The body of the column, which reaches between the base and capital, is termed the Shaft : it is the frustrum of a cone, with sometimes a plain surface,but frequently having perpendicular flutings either meeting in an edge, or leaving a small plane space between them. The lintelling or covering, which lies upon and connects the columns, is termed the Entabla ture, and is sub-divided into three parts, named Archi trave, Frieze, and Cornice : The architrave consists of a mere lintel laid along the tops of the columns ; the frieze represents the ends of the cross beams resting upon the former, and having the spaces between filled up, having also a moulding fixed to conceal the horizontal joint, and divide it from the architrave ; and the upper member or cornice represents the projecting caves of a Greek roof, sheaving the ends of the rafters. The whole is distinctly exemplified in the first Greek or Doric order ; the ear liest instances of which exhibit Egyptian character, and proportions adapted to the climate and materials of Greece ; the column of the Doric being as gross in pro portion to its height as the pillars of the Thebaid ; but Greece being subject to rains, it was found necessary to elevate the whole edifice on an artificial platform, and cover it with a pointed roof, having projecting eaves, thus constituting features totally different from Egyp tian. The three Greek orders, named Doric, Ionic, and Corinthian, have the same principal members and sub divisions, but the dimensions, mouldings, and decorations, vary very considerably, as will be seen by the specimens of each, which will, in the course of this investigation, be produced.
It is only in Greece, or in the territories of Greek colonies, that pure specimens of these orders have been found. Their mouldings exhibit every specimen of conic section, as elliptical, parabolical, hyperbolical ; some arc merely champhercd : the circle was seldom employed, excepting in small cavettos and mouldings of contrary flexures.