LLOYD, Ll. S., A Musical Slide-Rule (Oxford University Press), 1938

140 x 220mm; pp. 25 [two card rules inserted to rear cover pouch]

This attractive little booklet, with the two parts of the slide rule tucked into a pouch on the rear cover, offers "an introduction to the study of the musical scale employed by composers and skilled artists" (from the Preface).

The slide rule carries two sets of scales, one of which is logarithmic. Lloyd introduces the logarithmic scale first, therefore teaching a little bit of mathematics along with quite a lot of musical theory.

The relationship between music and mathematics is deep and long-standing. The use of calculating instruments in music is less well known.

Very good condition: cover very slightly spotted; rear cover creased to the lower left corner; internally very good, noting only some rusting to the staples.