94 Mr. H, Eeathcote Statham [Jan. 31, 



structure : and the aesthetic expression which is true for a lintel 

 building cannot be true for an arched building. This was exactly 

 what the Eomans, who were great engineers but bad artists, did not 

 perceive. They could not invent an architectural expression of their 

 own ; they faced their arched constructions with a mask borrowed 

 from the columnar architecture of the Greeks (Fig. 6), but having no 

 reference to the real construction of the building, which in fact it 

 contradicted : or they interposed a slice of the Greek lintel super- 

 structure uselessly between the capital and the arch which should 

 have sprung from it (Fig. 7) ; being accustomed to see a column 

 carry an architrave and cornice, they could not conceive its existence 

 without these members even when their use and meaning were gone. 

 Their design was therefore aesthetically false and illogical. 



Let us consider the problem of the arched building a little more 

 in detail. Its simplest form is what is called a " barrel-vaulted " 

 building, roofed by a continuous arch from end to end (Fig. 10). To 

 resist the expansive thrust of this arch we must have very thick walls, 

 so as to keep the line of pressure within the thickness of the wall, the 

 equilibrium of which is otherwise endangered : but this again is a 

 method very wasteful of material. If, however, we can introduce cross- 

 arches intersecting the main arch (11), we find the result is to collect 

 the pressure of the arches at certain equidistant points along the wall, 

 and if we can secure these points, we can afford to build the intervening 

 portions almost as thin as we like, or even (theoretically) to omit the 

 wall altogether between the points of support, as it does nothing towards 

 carrying the arches. Leaving for a moment the question of the treat- 

 ment of these supporting points or piers, we have one or two more 

 difficulties to contend with in our arched construction. A circular 

 arch on a large scale has practically a tendency to sink at the crown, 

 the joints on either side of the keystone becoming so nearly vertical 

 as to allow of the stone slipping under the influence of very slight 

 settlement in the abutments ; and this danger is increased in the 

 cross-vaulting, where the oblique arch formed by the intersecting 

 vaulting surfaces is an ellipse, and therefore still flatter at the crown. 

 But a new difficulty meets us again as soon we have to cross-vault a 

 space which is not a square (12), but is larger on one side than the 

 other. For as the two intersecting arches must rise to the same height, 

 and as the relation of height to width is rigidly fixed in the semi- 

 circular arch, we must cither employ a segment of a circle only for the 

 wider arch (12a), or else spring the smaller one from a higher point 

 than the other (126), so that the crowns of the two may coincide in 

 height. The latter expedient (called " stilting " the arch) was the one 

 usually adopted by the Koman and Romanesque builders; but the 

 effect in either case is that the oblique arch formed by the intersection 

 of these two curves of different elements gives a crippled and sinuous 

 line very unsightly and weak in appearance. 



These three difficulties with the round arch are what made Gothic 

 architecture, the architecture of pointed arches and buttresses, which 



