Читать книгу The Stones of Venice (Vol. 1-3) - John Ruskin - Страница 22

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§ I. We have hitherto considered the aperture as merely pierced in the thickness of the walls; and when its masonry is simple and the fillings of the aperture are unimportant, it may well remain so. But when the fillings are delicate and of value, as in the case of colored glass, finely wrought tracery, or sculpture, such as we shall often find occupying the tympanum of doorways, some protection becomes necessary against the run of the rain down the walls, and back by the bevel of the aperture to the joints or surface of the fillings.

§ II. The first and simplest mode of obtaining this is by channelling the jambs and arch head; and this is the chief practical service of aperture mouldings, which are otherwise entirely decorative. But as this very decorative character renders them unfit to be made channels for rain water, it is well to add some external roofing to the aperture, which may protect it from the run of all the rain, except that which necessarily beats into its own area. This protection, in its most usual form, is a mere dripstone moulding carried over or round the head of the aperture. But this is, in reality, only a contracted form of a true roof, projecting from the wall over the aperture; and all protections of apertures whatsoever are to be conceived as portions of small roofs, attached to the wall behind; and supported by it, so long as their scale admits of their being so with safety, and afterwards in such manner as may be most expedient. The proper forms of these, and modes of their support, are to be the subject of our final enquiry.

Fig. XLVIII.

§ III. Respecting their proper form we need not stay long in doubt. A deep gable is evidently the best for throwing off rain; even a low gable being better than a high arch. Flat roofs, therefore, may only be used when the nature of the building renders the gable unsightly; as when there is not room for it between the stories; or when the object is rather shade than protection from rain, as often in verandahs and balconies. But for general service the gable is the proper and natural form, and may be taken as representative of the rest. Then this gable may either project unsupported from the wall, a, Fig. XLVIII., or be carried by brackets or spurs, b, or by walls or shafts, c, which shafts or walls may themselves be, in windows, carried on a sill; and this, in its turn, supported by brackets or spurs. We shall glance at the applications of each of these forms in order.

§ IV. There is not much variety in the case of the first, a, Fig. XLVIII. In the Cumberland and border cottages the door is generally protected by two pieces of slate arranged in a gable, giving the purest possible type of the first form. In elaborate architecture such a projection hardly ever occurs, and in large architecture cannot with safety occur, without brackets; but by cutting away the greater part of the projection, we shall arrive at the idea of a plain gabled cornice, of which a perfect example will be found in Plate VII. of the folio series. With this first complete form we may associate the rude, single, projecting, penthouse roof; imperfect, because either it must be level and the water lodge lazily upon it, or throw off the drip upon the persons entering.

§ V. 2. b, Fig. XLVIII. This is a most beautiful and natural type, and is found in all good architecture, from the highest to the most humble: it is a frequent form of cottage door, more especially when carried on spurs, being of peculiarly easy construction in wood: as applied to large architecture, it can evidently be built, in its boldest and simplest form, either of wood only, or on a scale which will admit of its sides being each a single slab of stone. If so large as to require jointed masonry, the gabled sides will evidently require support, and an arch must be thrown across under them, as in Fig. XLIX., from Fiesole.

Fig. XLIX.

If we cut the projection gradually down, we arrive at the common Gothic gable dripstone carried on small brackets, carved into bosses, heads, or some other ornamental form; the sub-arch in such case being useless, is removed or coincides with the arch head of the aperture.

§ VI. 3. c, Fig. XLVIII. Substituting walls or pillars for the brackets, we may carry the projection as far out as we choose, and form the perfect porch, either of the cottage or village church, or of the cathedral. As we enlarge the structure, however, certain modifications of form become necessary, owing to the increased boldness of the required supporting arch. For, as the lower end of the gabled roof and of the arch cannot coincide, we have necessarily above the shafts one of the two forms a or b, in Fig. L., of which the latter is clearly the best, requiring less masonry and shorter roofing; and when the arch becomes so large as to cause a heavy lateral thrust, it may become necessary to provide for its farther safety by pinnacles, c.

This last is the perfect type of aperture protection. None other can ever be invented so good. It is that once employed by Giotto in the cathedral of Florence, and torn down by the proveditore, Benedetto Uguccione, to erect a Renaissance front instead; and another such has been destroyed, not long since, in Venice, the porch of the church of St. Apollinare, also to put up some Renaissance upholstery: for Renaissance, as if it were not nuisance enough in the mere fact of its own existence, appears invariably as a beast of prey, and founds itself on the ruin of all that is best and noblest. Many such porches, however, happily still exist in Italy, and are among its principal glories.

Fig. L.

§ VII. When porches of this kind, carried by walls, are placed close together, as in cases where there are many and large entrances to a cathedral front, they would, in their general form, leave deep and uncomfortable intervals, in which damp would lodge and grass grow; and there would be a painful feeling in approaching the door in the midst of a crowd, as if some of them might miss the real doors, and be driven into the intervals, and embayed there. Clearly it will be a natural and right expedient, in such cases, to open the walls of the porch wider, so that they may correspond in slope, or nearly so, with the bevel of the doorway, and either meet each other in the intervals, or have the said intervals closed up with an intermediate wall, so that nobody may get embayed in them. The porches will thus be united, and form one range of great open gulphs or caverns, ready to receive all comers, and direct the current of the crowd into the narrower entrances. As the lateral thrust of the arches is now met by each other, the pinnacles, if there were any, must be removed, and waterspouts placed between each arch to discharge the double drainage of the gables. This is the form of all the noble northern porches, without exception, best represented by that of Rheims.

§ VIII. Contracted conditions of the pinnacle porch are beautifully used in the doors of the cathedral of Florence; and the entire arrangement, in its most perfect form, as adapted to window protection and decoration, is applied by Giotto with inconceivable exquisiteness in the windows of the campanile; those of the cathedral itself being all of the same type. Various singular and delightful conditions of it are applied in Italian domestic architecture (in the Broletto of Monza very quaintly), being associated with balconies for speaking to the people, and passing into pulpits. In the north we glaze the sides of such projections, and they become bow-windows, the shape of roofing being then nearly immaterial and very fantastic, often a conical cap. All these conditions of window protection, being for real service, are endlessly delightful (and I believe the beauty of the balcony, protected by an open canopy supported by light shafts, never yet to have been properly worked out). But the Renaissance architects destroyed all of them, and introduced the magnificent and witty Roman invention of a model of a Greek pediment, with its cornices of monstrous thickness, bracketed up above the window. The horizontal cornice of the pediment is thus useless, and of course, therefore, retained; the protection to the head of the window being constructed on the principle of a hat with its crown sewn up. But the deep and dark triangular cavity thus obtained affords farther opportunity for putting ornament out of sight, of which the Renaissance architects are not slow to avail themselves.

A more rational condition is the complete pediment with a couple of shafts, or pilasters, carried on a bracketed sill; and the windows of this kind, which have been well designed, are perhaps the best things which the Renaissance schools have produced: those of Whitehall are, in their way, exceedingly beautiful; and those of the Palazzo Ricardi at Florence, in their simplicity and sublimity, are scarcely unworthy of their reputed designer, Michael Angelo.