§ 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. FOOTNOTES: [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. CHAPTER XVIII. PROTECTION OF APERTURE.