La musique enseignée par l'intuition. Usage du Tonoscope-harmonium dans l'exposé et la démonstration des lois de la science musicale - Christiaens, Emile (Paris Brussels Au Ménestrel Maison Beethoven, 1880)
From "La Belgique à l'exposition universelle de 1878": ... Emile Christiaens was struck by the fact that, in the essentially abstract intelligence of the first notions of music, the teacher cannot use any intuitive means. He wanted to fill this gap. He thought that, thanks to the close links between the different senses, we should be able to train the ear through sight, and however strange the problem may seem, he managed to solve it. He therefore constructed a new instrument to which he gave a name that these few words make intelligible. It would be more difficult to describe it than to justify its name. The tonoscope consists of a case containing the organs of a harmonium with blower, and on one of the outer walls of the case, the front wall, there are two keyboards separated by a free space. You can slide from one end to the other, a movable piece which the author calls a transpositor and which highlights the shape of the diatonic scale and the invariable relationship between the major and minor modes. The whole is a tableau designed to demonstrate the laws of tonality and transposition, the fundamental laws of harmony.
Système approuvé par le gouvernement Belge et admis pour l'enseignement normal officiel
Keywords: 19th Century (1801-1900); Reed organ; Harmony; Method; Organology; Transposition