"If the use of iron in building does not enable us to exceed these dimensions at a decidedly less cost, then indeed we are inferior to our ancestors. In fact the great builders of the Middle Ages, like those of the Renaissance, were eminently men of subtle, active, and inventive intellect. I say inventive intellect, for that is the ruling characteristic of the works bequeathed to us by those old builders. It is apparent in the structure of our mediaeval buildings, and only ceases to manifest itself when the material becomes inadequate. It is apparent in the attempts of the Renaissance; for apart from the superficial imitation of classic forms which the architects of the latter period affected, they did not adhere to this imitation in the construction of their buildings and in the methods they employed. Without reference to the buildings of that epoch, we may find the proof of this fact in the written works of several of those architects, such as Albert Dürer, Serlio, Philibert de l'Orme, etc. On every page of their writings we find some original idea, or new adaptation; and as in the case of their predecessors, their ingenuity is circumscribed only by the inadequacy of their materials."