An acclaimed Welsh singer and philanthropist, Margaret Watts Hughes (1842–1907) was the inventor of the eidophone, a device used to create images of sound that she called “Voice Figures.” While Hughes valued her discovery for both its scientific and spiritual implications, leaders of the Theosophical movement saw her work as a means of making visible the invisible world. Margaret Watts Hughes: Sound May Be Seen presents selections from Watts Hughes’ original publication of the “Voice Figures” and a rare surviving set of her glass slides alongside contemporary reactions to her captivating and ultimately enigmatic work.