LITMIR.BIZ

      § V. 2. Roofs.—A roof is the covering of a space, narrow or wide. It will be most conveniently studied by first considering the forms in which it may be carried over a narrow space, and then expanding these on a wide plan; only there is some difficulty here in the nomenclature, for an arched roof over a narrow space has (I believe) no name, except that which belongs properly to the piece of stone or wood composing such a roof, namely, lintel. But the reader will have no difficulty in understanding that he is first to consider roofs on the section only, thinking how best to construct a narrow bar or slice of them, of whatever form; as, for instance, x, y, or z, over the plan or area a, Fig. I. Having done this, let him imagine these several divisions, first moved along (or set side by side) over a rectangle, b, Fig. I., and then revolved round a point (or crossed at it) over a polygon, c, or circle, d, and he will have every form of simple roof: the arched section giving successively the vaulted roof and dome, and the gabled section giving the gabled roof and spire.

      As we go farther into the subject, we shall only have to add one or two forms to the sections here given, in order to embrace all the uncombined roofs in existence; and we shall not trouble the reader with many questions respecting cross-vaulting, and other modes of their combination.

      § VI. Now, it also happens, from its place in buildings, that the sectional roof over a narrow space will need to be considered before we come to the expanded roof over a broad one. For when a wall has been gathered, as above explained, into piers, that it may better bear vertical pressure, it is generally necessary that it should be expanded again at the top into a continuous wall before it carries the true roof. Arches or lintels are, therefore, thrown from pier to pier, and a level preparation for carrying the real roof is made above them. After we have examined the structure of piers, therefore, we shall have to see how lintels or arches are thrown from pier to pier, and the whole prepared for the superincumbent roof; this arrangement being universal in all good architecture prepared for vertical pressures: and we shall then examine the condition of the great roof itself. And because the structure of the roof very often introduces certain lateral pressures which have much to do with the placing of buttresses, it will be well to do all this before we examine the nature of buttresses, and, therefore, between parts (B) and (C) of the above plan, § IV. So now we shall have to study: (A) the construction of walls; (B) that of piers; (C) that of lintels or arches prepared for roofing; (D) that of roofs proper; and (E) that of buttresses.

      § VII. 3. Apertures.—There must either be intervals between the piers, of which intervals the character will be determined by that of the piers themselves, or else doors or windows in the walls proper. And, respecting doors or windows, we have to determine three things: first, the proper shape of the entire aperture; secondly, the way in which it is to be filled with valves or glass; and thirdly, the modes of protecting it on the outside, and fitting appliances of convenience to it, as porches or balconies. And this will be our division F; and if the reader will have the patience to go through these six heads, which include every possible feature of protective architecture, and to consider the simple necessities and fitnesses of each, I will answer for it, he shall never confound good architecture with bad any more. For, as to architecture of position, a great part of it involves necessities of construction with which the spectator cannot become generally acquainted, and of the compliance with which he is therefore never expected to judge,—as in chimneys, light-houses, &c.: and the other forms of it are so closely connected with those of protective architecture, that a few words in Chap. XIX. respecting staircases and towers, will contain all with which the reader need be troubled on the subject.

CHAPTER IV.

      THE WALL BASE

      § I. Our first business, then, is with Wall, and to find out wherein lies the true excellence of the “Wittiest Partition.” For it is rather strange that, often as we speak of a “dead” wall, and that with considerable disgust, we have not often, since Snout’s time, heard of a living one. But the common epithet of opprobrium is justly bestowed, and marks a right feeling. A wall has no business to be dead. It ought to have members in its make, and purposes in its existence, like an organized creature, and to answer its ends in a living and energetic way; and it is only when we do not choose to put any strength nor organization into it, that it offends us by its deadness. Every wall ought to be a “sweet and lovely wall.” I do not care about its having ears; but, for instruction and exhortation, I would often have it to “hold up its fingers.” What its necessary members and excellences are, it is our present business to discover.

      § II. A wall has been defined to be an even and united fence of wood, earth, stone, or metal. Metal fences, however, seldom, if ever, take the form of walls, but of railings; and, like all other metal constructions, must be left out of our present investigation; as may be also walls composed merely of light planks or laths for purposes of partition or inclosure. Substantial walls, whether of wood or earth (I use the word earth as including clay, baked or unbaked, and stone), have, in their perfect form, three distinct members;—the Foundation, Body or Veil, and Cornice.

      § III. The foundation is to the wall what the paw is to an animal. It is a long foot, wider than the wall, on which the wall is to stand, and which keeps it from settling into the ground. It is most necessary that this great element of security should be visible to the eye, and therefore made a part of the structure above ground. Sometimes, indeed, it becomes incorporated with the entire foundation of the building, a vast table on which walls or piers are alike set: but even then, the eye, taught by the reason, requires some additional preparation or foot for the wall, and the building is felt to be imperfect without it. This foundation we shall call the Base of the wall.

      § IV. The body of the wall is of course the principal mass of it, formed of mud or clay, of bricks or stones, of logs or hewn timber; the condition of structure being, that it is of equal thickness everywhere, below and above. It may be half a foot thick, or six feet thick, or fifty feet thick; but if of equal thickness everywhere, it is still a wall proper: if to its fifty feet of proper thickness there be added so much as an inch of thickness in particular parts, that added thickness is to be considered as some form of buttress or pier, or other appliance.33

      In perfect architecture, however, the walls are generally kept of moderate thickness, and strengthened by piers or buttresses; and the part of the wall between these, being generally intended only to secure privacy, or keep out the slighter forces of weather, may be properly called a Wall Veil. I shall always use this word “Veil” to signify the even portion of a wall, it being more expressive than the term Body.

      § V. When the materials with which this veil is built are very loose, or of shapes which do not fit well together, it sometimes becomes necessary, or at least adds to security, to introduce courses of more solid material. Thus, bricks alternate with rolled pebbles in the old walls of Verona, and hewn stones with brick in its Lombard churches. A banded structure, almost a stratification of the wall, is thus produced; and the courses of more solid material are sometimes decorated with carving. Even when the wall is not thus banded through its whole height, it frequently becomes expedient to lay a course of stone, or at least of more carefully chosen materials, at regular heights; and such belts or bands we may call String courses. These are a kind of epochs in the wall’s existence; something like periods of rest and reflection in human life, before entering on a new career. Or else, in the building, they correspond to the divisions of its stories within, express its internal structure, and mark off some portion of the ends of its existence already attained.

      § VI. Finally, on the top of the wall some protection from the weather is necessary, or some preparation for the reception of superincumbent weight, called a coping, or Cornice. I shall use the word Cornice for both; for, in fact, a coping is a roof to the wall itself, and is carried by a small cornice

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