MERSENNE, MARIN. Harmonicorum libri in quibus agitur de sonorum natura, causis & effectibus: de consonantiis, dissonantiis, rationibus, generibus, modis, cantibus, compositione, orbisque totius harmonicis instrumentis. Paris: Guillaume Baudry, 1635. 21 engraved illustrations and more than 100 woodcut illustrations mainly of musical instruments. 2 vols. in one, folio, rebound in later vellum; lacks R6 and x4 in vol. I (as often) and in vol. II x2-x3, last leaf repaired; light marginal dampstaining. FIRST EDITION. The second volume is an important study on musical instruments of the late Renaissance and early Baroque periods. The signatures R and X are sometimes replaced by single cancel-leaves, but are often missing altogether. Brunet III:1662. Sold not subject to return.