designed it, or it may express the facts of its own internal structure and arrangement.  The former, however, can only, I think, be said to be realized in the case of architecture of the highest class, and when taken collectively as a typical style.  For instance, we can all pretty well agree that the mediaeval cathedral expresses an emotion of aspiration on the part of its builders.  The age that built the cathedrals longed to soar in some way, and this was the way then open to it, and it sent up its soul in spreading vaults, and in pinnacles and spires.  So also we can never look at Greek architecture without seeing in it the reflection of a nature refined, precise, and critical; loving grace and finish, but content to live with the graces and the muses without any aspirations that spurned this earth.  We can hardly go further than this in attributing emotional expression to architecture.  But in a more restricted sense of the word expression, a building may express very definitely its main constructive facts, its plan and arrangement, to a certain extent even its purpose, so far at least that we may be able to identify the class of structure to which it belongs.  It not only may, but it ought to do this, unless the architecture is to be a mere ornamental screen for concealing the prosaic facts of the structure.  There is a good deal of architecture in the world which is in fact of this kind—­an ornamental screen unconnected with the constructional arrangement of the building.  Nor is such architecture to be entirely scouted.  It may be a very charming piece of scenery in itself, and you may even make a very good theoretical defense for it, from a certain point of view.  But on the whole, architecture on that principle becomes uninteresting.  You very soon tire of it.  It is a mask rather than a countenance, and tends to the production of a dull uniformity of conventional design.

For we must remember that architecture, although a form of artistic expression, is not, like painting and sculpture, unfettered by practical considerations.  It is an art inextricably bound up with structural conditions and practical requirements.  A building is erected first for convenience and shelter; secondly only for appearance, except in the case of such works as monuments, triumphal arches, etc., which represent architectural effect pure and simple, uncontrolled by practical requirements.  With such exceptions, therefore, a building ought to express in its external design its internal planning and arrangement; in other words, the architectural design should arise out of the plan and disposition of the interior, or be carried on concurrently with it, not designed as a separate problem.  Then a design is dependent on structural conditions also, and if these are not observed, the building does not stand, and hence it is obvious that the architectural design must express these structural conditions.  It must not appear to stand or be constructed in a way in which it could not stand (like