140 TRANSACTIONS OF THE 
move backward. By this means and by other simple devices, 
the reading of the tonoscope is comparatively easy, thus 
making it possible to train the voice by means of the eye. 
Measurements have been made with this instrument 
on the ability to strike a pitch, to sustain a tone and to 
modulate a tone. The vowel sounds have been analyzed 
and their characteristic qualities revealed. The tonoscope 
has already demonstrated its utility in discovering musical 
ability and promises large returns in a specific field of ap- 
plied psychology. 
2W. R. Miles. Accuracy of Voice in Simple Pitch Singing. Psychologi- 
cal Monographs. No. 69, pp. 13-66. 
