Music.- Proportio Harmonica Tonorum

Music.- Proportio Harmonica Tonorum, or, The true distance of Musical Notes: As the same is Mathematically proved and brought to ocular Demonstration,manuscript, title and 94pp., 2 folding pen and ink illustrations (1 with grey pencil), slightly browned, original grey card, rubbed and slightly discoloured, manuscript title on upper cover, spine chipped, edges uncut, sm. 4to, [eighteenth century].