Another very great, though little regarded point of excellence and architectural effect in the latter consists in the covered ambulatories and porticoes, which, indeed, were intended chiefly as a defence against heat and sun, yet recommend themselves equally to us, as affording protection from rain and wind. Nevertheless it is rarely but in cloisters that we find this architectural convenience retained. Great attention seems also to have been paid by the ancients to planning the internal communication in such a manner, that the domestics could pass to and fro, and have access to the different rooms, without incommoding those occupying any of the suite; and in this sort of arrangement they frequently exhibit so much ingenuity and contrivance, that we may study for some time ere we shall be able to surpass them. For the present, these few hints and suggestions must suffice; but I could discourse to you for days together of the varied effects of light, the manifold diversity of form, the richness of play in regard to decoration, and all the combinations and beauties, both with respect to circumstances of locality and arrangement, that are to be met with in the remains of ancient domestic architecture. Among other questions which you have submitted for my consideration, is, whether pure Greek architectural forms and details will bear to be united with such a material as coloured brickwork? And by way of removing your doubts, I beg to remind you of the highly praised brick edifices of King Mausolus, described by Vitruvius. Texture and colour of materials are to be considered merely as the vehicle made use of by the artist, and may be employed in one style almost equally as well as in another. Another doubt suggested, is whether arches and vaulting can properly be admitted into the style above-named? Now, were you to consult the Delphic oracle, it would probably return you some such answer as the following: _When the edge of an aperture in a wall forms a right angle, the archivolt may still descend to the base without being interrupted by an impost. In vaulting, the diagonal crossing lines must be considered as secondary ones._ Perhaps this will but ill satisfy you, and you will say that, instead of solving one enigma, I have merely added another. Yet of one thing you may be assured, namely, that those difficult problems and mysteries in art, which have been expounded in formal terms, have been already actually decyphered, and explained more clearly by the practical solution of them in productions of art.