The two following, on "Ornament from Mathematics," represent a recasting and a rewriting of articles which have appeared in _The Architectural Review, The Architectural Forum_, and _The American Architect_. "Harnessing the Rainbow" is an address delivered before the Ad. Club of Cleveland, and the Rochester Rotary Club, and afterwards made into an essay and published in _The American Architect_ under a different title. The appreciation of Louis Sullivan as a writer appears here for the first time, the author having previously paid his respects to Mr. Sullivan's strictly architectural genius in an essay in _House and Garden_