to guard against in recent times, is one which, nevertheless, comes in a "questionable shape," and of which it is not easy to determine the proper laws and limits; I mean the use of iron. The definition of the art of architecture, given in the first chapter, is independent of its materials: nevertheless, that art having been, up to the beginning of the present century, practised for the most part in clay, stone, or wood, it has resulted that the sense of proportion and the laws of structure have been based, the one altogether, the other in great part, on the necessities consequent on the employment of those materials; and that the entire or principal employment of metallic framework would, therefore, be generally felt as a departure from the first principles of the art. Abstract[Pg 44]edly there appears no reason why iron should not be used as well as wood; and the time is probably near when a new system of architectural laws will be developed, adapted entirely to metallic construction. But I believe that the tendency of all present sympathy and association is to limit the idea of architecture to non-metallic work; and that not without reason. For architecture being in its perfection the earliest, as in its elements it is necessarily the first, of arts, will always precede, in any barbarous nation, the possession of the science necessary either for the obtaining or the management of iron. Its first existence and its earliest laws must, therefore, depend upon the use of materials accessible in quantity, and on the surface of the earth; that is to say, clay, wood, or stone: and as I think it cannot but be generally felt that one of the chief dignities of architecture is its historical use; and since the latter is partly dependent on consistency of style, it will be felt right to retain as far as may be, even in periods of more advanced science, the materials and principles of