Sentence:  [The Committee on Allied Arts] hopes that the Committee on Publicity and the Journal of the Institute may be instructed to spread abroad, as a fundamental Institute principle, the belief that sympathetic, intelligent collaboration among the <WSD>allied arts</WSD> is, and always has been, the only sure road to a worthy architecture in any age or any land. 
Meaning of the word marked with <WSD> tags:  The decorative arts as applied to buildings.