ARCHITECTURE. 



ture be impaired ; this is to be seen in the 

 theatre of Marcellus ; but when the sto- 

 ries of orders are insulated, it is necessary 

 that the axis of the superior and inferior 

 columns should be in the same vertical 

 lines. If the upper order only insists in 

 tlie middle of that below in two equidis- 

 tant parts from the middle, the portions 

 of the entablature of the lower order, in 

 which there is no superior order, are 

 generally finished with a ballustrade, 

 level with the sills of the windows. 



In England we have few examples of 

 more than two ranges of columns in the 

 same front ; for when there are three, it is 

 difficult to preserve the character of each 

 order in the intercolumnial decorations, 

 without some striking defects. The first 

 and second orders should stand upon a 

 plinth, and the third also, when there is 

 one, the point of view regulating the two 

 upper plinths. In this case pedestals 

 should be omitted in the upper orders, 

 and if there is one, or a ballustrade under 

 the windows, the base and cornice should 

 have but a small projection, and should 

 be continued to profile upon the sides of 

 the columns. In raising the stories of ar- 

 cades upon each other, with orders deco- 

 rating the piers, the inferior columns 

 should be placed upon a plinth,andthesu- 

 perior ones upon a pedestal, in order that 

 the arches may obtain a just proportion. 

 Pediments. A pediment is a part of a 

 building having a horizontal cornice be- 

 low, and two equally inclined ones, or an 

 arched cornice, above, joined at the ex- 

 tremities of the horizontal one; the cor- 

 nices including a plane surface within, 

 called the tympanum, which is therefore 

 either a triangle or the segment of a circle. 

 This definition does not comprehend 

 every species of pediments which have 

 been absurdly introduced ; but it may be 

 said to be the only genuine one, as pedi- 

 ments represent the ends of roofs, and 

 were originally intended to discharge the 

 ram from the middle of the building, by 

 compelling it to descend and fall over the 

 flanks or extremes, and not over the front, 

 which must be the case with every other 

 figure that can be introduced, except 

 those of a polygonal form, which present 

 their interior angles to the horizontal 

 cornice, or the exterior ones upwards. 

 To find the pitch of the pediment Vitru- 

 vius directs as follows : divide between 

 the extremities of the cymatium of the 

 corona into nine equal parts, and one 

 makes the height of the tympanum j but 

 this rule is not correct, as the tympanum 

 will vary its angles according as there 



are more or less mouldings of the inclined 

 cornices within the extremities of the cy- 

 matium of the corona ; for since the mid- 

 dle part by this rule is invariable, and the 

 broader the parts are of the inclined cor- 

 nices within each extremity of the cyma- 

 tium of the corona, or rather within the 

 under edge of the fillet of the syma upon 

 each inclined cornice, the less is the base of 

 the tympanum, and consequentlythe ver- 

 tical angle less obtuse, and the base angles 

 less acute ; but if this height extended to 

 the meeting of the two under sides of the 

 fillets of the syma, or crowning moulding, 

 then the figure of the tympanum would be 

 invariable. The Vitruvian rule has been 

 thought by many to be too low; but it is to 

 be recollected, that that of the Parthenon 

 at Athens, which has an octostyle portico, 

 is nearly of this proportion ; that of the 

 temple of Theseus, which has an hexa- 

 style portico, is about one-eighth ; that of 

 the Ionic temple on the Ilyssus, and of 

 the Doric portico, which are both tetra- 

 style, are about one-seventh ; the tympa- 

 num of the pediment of the door on the 

 Tower of the Winds is about one-fifth of 

 the span. The edifices here mentioned 

 are all Athenian buildings. From this 

 comparison it would appear, that a kind 

 of reciprocal ratio subsists between the 

 extension of the base of the tympanum 

 and its height. Indeed, if a fixed ratio 

 were applied to windows, the pediment 

 would frequently consist of a cornice, 

 without the tympanum. It is therefore 

 with great reason that we often make the 

 pitch of pediments of windows more than 

 those which crown porticos, or the fronts 

 of buildings. The plinths by which pedi- 

 ments are sometimes decorated are call- 

 ed acroterions, or acroters : the two 

 which present triangular faces at the ex- 

 tremes have their heights, according to 

 Vitruvius, half of that of the tympanum, 

 and the middle one saddled on the sum- 

 mit is one-eighth part higher than those 

 at the extremes. Pediments owe their 

 origin most probably to the inclined roofs 

 of primitive huts. Among the Romans 

 they were only used as coverings to their 

 sacred buildings, till Caesar obtainedleave 

 to cover his house with a pointed roof, 

 after the manner of temples. In Gre- 

 cian antiquity we meet only with tri- 

 angular pediments, and in Roman build- 

 ings we meet with both the triangular and 

 circular. In rows of openings, or niches, 

 both kinds of pediments were employed 

 in the same range, and disposed in alter- 

 nate succession. The horizontal cornices 

 of pediments should never be discontinu- 



