147. From these principles of simplicity and temperance, two very severely fixed laws of construction follow; namely, first, that our structure, to be beautiful, must be produced with tools of men; and, secondly, that it must be composed of natural substances. First, I say, produced with tools of men. All fine art requires the application of the whole strength and subtlety of the body, so that such art is not possible to any sickly person, but involves the action and force of a strong man's arm from the shoulder, as well as the delicatest touch of his fingers: and it is the evidence that this full and fine strength has been spent on it which makes the art executively noble; so that no instrument must be used, habitually, which is either too heavy to be delicately restrained, or too small and weak to transmit a vigorous impulse; much less any mechanical aid, such as would render the sensibility of the fingers ineffectual.[29]
148. Of course, any kind of work in glass, or in metal, on a large scale, involves some painful endurance of heat; and working in clay, some habitual endurance of cold; but the point beyond which the effort must not be carried is marked by loss of power of manipulation. As long as the eyes and fingers have complete command of the material, (as a glass-blower has, for instance, in doing fine ornamental work,)—the law is not violated; but all our great engine and furnace work, in gun-making and the like, is degrading to the intellect; and no nation can long persist in it without losing many of its human faculties. Nay, even the use of machinery other than the common rope and pulley, for the lifting of weights, is degrading to architecture; the invention of expedients for the raising of enormous stones has always been a characteristic of partly savage or corrupted races. A block of marble not larger than a cart with a couple of oxen could carry, and a cross-beam, with a couple of pulleys, raise, is as large as should generally be used in any building. The employment of large masses is sure to lead to vulgar exhibitions of geometrical arrangement,[30] and to draw away the attention from the sculpture. In general, rocks naturally break into such pieces as the human beings that have to build with them can easily lift; and no larger should be sought for.
149. In this respect, and in many other subtle ways, the law that the work is to be with tools of men is connected with the farther condition of its modesty, that it is to be wrought in substance provided by Nature, and to have a faithful respect to all the essential qualities of such substance.
And here I must ask your attention to the idea, and, more than idea,—the fact, involved in that infinitely misused term, 'Providentia,' when applied to the Divine power. In its truest sense and scholarly use, it is a human virtue, Προμηθεια; the personal type of it is in Prometheus, and all the first power of τεχνη, is from him, as compared to the weakness of days when men without foresight "εφυρον εικη παντα." But, so far as we use the word 'Providence' as an attribute of the Maker and Giver of all things, it does not mean that in a shipwreck He takes care of the passengers who are to be saved, and takes none of those who are to be drowned; but it does mean that every race of creatures is born into the world under circumstances of approximate adaptation to its necessities; and, beyond all others, the ingenious and observant race of man is surrounded with elements naturally good for his food, pleasant to his sight, and suitable for the subjects of his ingenuity;—the stone, metal, and clay of the earth he walks upon lending themselves at once to his hand, for all manner of workmanship.
150. Thus, his truest respect for the law of the entire creation is shown by his making the most of what he can get most easily; and there is no virtue of art, nor application of common sense, more sacredly necessary than this respect to the beauty of natural substance, and the ease of local use; neither are there any other precepts of construction so vital as these—that you show all the strength of your material, tempt none of its weaknesses, and do with it only what can be simply and permanently done.
151. Thus, all good building will be with rocks, or pebbles, or burnt clay, but with no artificial compound; all good painting with common oils and pigments on common canvas, paper, plaster, or wood,—admitting sometimes, for precious work, precious things, but all applied in a simple and visible way. The highest imitative art should not, indeed, at first sight, call attention to the means of it; but even that, at length, should do so distinctly, and provoke the observer to take pleasure in seeing how completely the workman is master of the particular material he has used, and how beautiful and desirable a substance it was, for work of that kind. In oil painting, its unctuous quality is to be delighted in; in fresco, its chalky quality; in glass, its transparency; in wood, its grain; in marble, its softness; in porphyry, its hardness; in iron, its toughness. In a flint country, one should feel the delightfulness of having flints to pick up, and fasten together into rugged walls. In a marble country, one should be always more and more astonished at the exquisite color and structure of marble; in a slate country, one should feel as if every rock cleft itself only for the sake of being built with conveniently.
152. Now, for sculpture, there are, briefly, two materials—Clay, and Stone; for glass is only a clay that gets clear and brittle as it cools, and metal a clay that gets opaque and tough as it cools. Indeed, the true use of gold in this world is only as a very pretty and very ductile clay, which you can spread as flat as you like, spin as fine as you like, and which will neither crack nor tarnish.
All the arts of sculpture in clay may be summed up under the word 'Plastic,' and all of those in stone, under the word 'Glyptic.'
153. Sculpture in clay will accordingly include all cast brickwork, pottery, and tile-work[31]—a somewhat important branch of human skill. Next to the potter's work, you have all the arts in porcelain, glass, enamel, and metal,—everything, that is to say, playful and familiar in design, much of what is most felicitously inventive, and, in bronze or gold, most precious and permanent.
154. Sculpture in stone, whether granite, gem, or marble, while we accurately use the general term 'glyptic' for it, may be thought of with, perhaps, the most clear force under the English word 'engraving.' For, from the mere angular incision which the Greek consecrated in the triglyphs of his greatest order of architecture, grow forth all the arts of bas-relief, and methods of localized groups of sculpture connected with each other and with architecture: as, in another direction, the arts of engraving and wood-cutting themselves.