Architecture is a chained and fettered art. Far from being "frozen music," it is an art constantly attempting to realize in solid, stable form those effects which music is able to conjure up in an instant—effects which succeed each other rapidly during the progress of a musical work. Music can attain the colossal in a way which, in architecture, only the rarest opportunities render even remotely possible. Music can, in a few moments, admit us through vast portals into avenues, courts and halls of infinite extent and variety. Music can suddenly raise up an entire structure and, by the device of modulation, lift it on to a podium, abruptly recess its facades and turn them bodily into the sunshine. Music can etch silhouettes ten times more intricate than those of Dresden or London City, repeat them, increase or reduce them, hurl them into the distance or bring them before us in precise detail. Most of the essentials of architecture—mass, rhythm, texture, outline—are within music's power. Almost, the two arts are the same art, the one able to express nearly everything which the imagination is capable of conceiving, the other bound by the rigours of economy and use.