Lightning Arranger Vintage 1930s for arranging orchestrations transposing music

Invented by Samuel "Skip," Rapoport, the Lightning Arranger, was a device for arranging orchestrations and transposing music. An oblong 2 3/4" x 4 1/2" celluloid device with two (2) side by side wheels, with eight (8) window openings on each side. One side is designed to find dominant and sub-dominant chords by setting both wheels to key. It includes Seventh Chords and Major Chords. The reverse is for all instruments, including pianos and violins tuned in C. One wheel represents Ninth Chords, the other Minor Chords. Originally, the inventor, Rapoport, had a booklet explaining chord progression and instructions for transposing and outlining chord structure. Rapoport said his device arranges music mathematically, the way music is arranged. It works by turning a wheel on the device, which in turn reveals the appropriate information on another part of the cardboard unit. It was manufactured for him by a New Jersey company. It claims to be a simplified method for arranging orchestrations. Literature on the device claims it's good for musicians, arrangers of music, band and choir directors, orchestra leaders, music instructors, supervisors, students of music, singers, accompanists, music teachers, beginners and composers. Title: Lightning Arranger - Device for arranging ... Publisher: Lightning Arranger, Allentown PA Publication Date: 1931