| Fig. XLVI. |
As thus. You find, in the first place (§ V.), that your tracery bars are to be subordinated, less to greater; so you take a group of, suppose, eight, which you make all exactly equal, giving you nine equal spaces in the window, as at A, [Fig. XLVI.] You found, in the second place (§ VII.), that there was no occasion for more than two cross bars; so you take at least four or five (also represented at A, [Fig. XLVI.]), also carefully equalised, and set at equal spaces. You found, in the third place (§ VIII.), that these bars were to be strengthened, in order to support the main piers; you will therefore cut the ends off the uppermost, and the fourth into three pieces (as also at A). In the fourth place, you found (§ IX.) that you were never to run a vertical bar into the arch head; so you run them all into it (as at B, [Fig. XLVI.]); and this last arrangement will be useful in two ways, for it will not only expose both the bars and the archivolt to an apparent probability of every species of dislocation at any moment, but it will provide you with two pleasing interstices at the flanks, in the shape of carving-knives, a, b, which, by throwing across the curves c, d, you may easily multiply into four; and these, as you can put nothing into their sharp tops, will afford you a more than usually rational excuse for a little bit of Germanism, in filling them with arches upside down, e, f. You will now have left at your disposal two and forty similar interstices, which, for the sake of variety, you will proceed to fill with two and forty similar arches: and, as you were told that the moment a bar received an arch heading, it was to be treated as a shaft and capitalled, you will take care to give your bars no capitals nor bases, but to run bars, foliations and all, well into each other after the fashion of cast-iron, as at C. You have still two triangular spaces occurring in an important part of your window, g g, which, as they are very conspicuous, and you cannot make them uglier than they are, you will do wisely to let alone;—and you will now have the west window of the cathedral of Winchester, a very perfect example of English Perpendicular. Nor do I think that you can, on the whole, better the arrangement, unless, perhaps, by adding buttresses to some of the bars, as is done in the cathedral at Gloucester; these buttresses having the double advantage of darkening the window when seen from within, and suggesting, when it is seen from without, the idea of its being divided by two stout party walls, with a heavy thrust against the glass.
§ XVII. Thus far we have considered the plan of the tracery only: we have lastly to note the conditions under which the glass is to be attached to the bars; and the sections of the bars themselves.
| Fig. XLVII. |
These bars we have seen, in the perfect form, are to become shafts; but, supposing the object to be the admission of as much light as possible, it is clear that the thickness of the bar ought to be chiefly in the depth of the window, and that by increasing the depth of the bar we may diminish its breadth: clearly, therefore, we should employ the double group of shafts, b, of [Fig. XIV.], setting it edgeways in the window: but as the glass would then come between the two shafts, we must add a member into which it is to be fitted, as at a, [Fig. XLVII.], and uniting these three members together in the simplest way, with a curved instead of a sharp recess behind the shafts, we have the section b, the perfect, but simplest type of the main tracery bars in good Gothic. In triforium and cloister tracery, which has no glass to hold, the central member is omitted, and we have either the pure double shaft, always the most graceful, or a single and more massy shaft, which is the simpler and more usual form.
§ XVIII. Finally: there is an intermediate arrangement between the glazed and the open tracery, that of the domestic traceries of Venice. Peculiar conditions, hereafter to be described, require the shafts of these traceries to become the main vertical supports of the floors and walls. Their thickness is therefore enormous; and yet free egress is required between them (into balconies) which is obtained by doors in their lattice glazing. To prevent the inconvenience and ugliness of driving the hinges and fastenings of them into the shafts, and having the play of the doors in the intervals, the entire glazing is thrown behind the pillars, and attached to their abaci and bases with iron. It is thus securely sustained by their massy bulk, and leaves their symmetry and shade undisturbed.
§ XIX. The depth at which the glass should be placed, in windows without traceries, will generally be fixed by the forms of their bevelling, the glass occupying the narrowest interval; but when its position is not thus fixed, as in many London houses, it is to be remembered that the deeper the glass is set (the wall being of given thickness), the more light will enter, and the clearer the prospect will be to a person sitting quietly in the centre of the room; on the contrary, the farther out the glass is set, the more convenient the window will be for a person rising and looking out of it. The one, therefore, is an arrangement for the idle and curious, who care only about what is going on upon the earth: the other for those who are willing to remain at rest, so that they have free admission of the light of Heaven. This might be noted as a curious expressional reason for the necessity (of which no man of ordinary feeling would doubt for a moment) of a deep recess in the window, on the outside, to all good or architectural effect: still, as there is no reason why people should be made idle by having it in their power to look out of window, and as the slight increase of light or clearness of view in the centre of a room is more than balanced by the loss of space, and the greater chill of the nearer glass and outside air, we can, I fear, allege no other structural reason for the picturesque external recess, than the expediency of a certain degree of protection, for the glass, from the brightest glare of sunshine, and heaviest rush of rain.
[58] “Seven Lamps,” p. 53.
[59] On the north side of the nave of the cathedral of Lyons, there is an early French window, presenting one of the usual groups of foliated arches and circles, left, as it were, loose, without any enclosing curve. The effect is very painful. This remarkable window is associated with others of the common form.