Instrumental music classes in the public schools of Tulsa, Oklahoma, have experienced a phenomenal growth during the past twenty years. Prior to this period, opportunity for instrumental music expression was limited to the high school band and orchestra,which rehearsed outside of school hours. No instruction other than this was provided and the student who wished to play in the school band or orchestra studied first from private instructors. In this study the investigator has examined a great many devices for measuring capacities and aptitudes which are known to the profession. He has attempted to evaluate these procedures in the light of sound educational philosophy. He has set forth a plan which he believes will materially improve the instrumental program through discovering unsuspected musical capacity and through sound guidance in the selection of suitable instruments.