Institutionum Calculi Integralis by EULER, Leonhard

One folding engraved plate. 2 p.l., 542 pp.; 2 p.l., 526, [8] pp.; 4 p.l., 639 pp. Three vols. in two. Large 4to, cont. speckled boards (neatly rebacked & recornered in antique mottled calf by Aquarius), entirely uncut, spines gilt. St. Petersburg: Impensis Academia Imperialis Scientiarum, 1768-69-70. First edition of the third and final classic contribution by Euler to analytical mathematics. "This series of works was completed by the publication in three volumes in 1768 to 1770 of the Institutiones Calculi Integralis, in which the results of several of Euler's earlier memoirs on the same subject and on differential equations are included. This, like the similar treatise on the differential calculus, summed up what was then known on the subject, but many of the theorems were recast and the proofs improved. The Beta and Gamma functions were invented by Euler and are discussed here..."­Ball, A Short Account of the History of Mathematics, p. 396. This work "exhibits Euler's numerous discoveries in the theory of both ordinary and partial differential equations, which were especially useful in mechanics."­D.S.B., IV, p. 478. The second edition of this work appeared posthumously between 1792 and 1794 with a fourth volume of unpublished material. This fourth volume is sometimes mistakenly described as belonging to the first edition. Some unimportant worming to first leaves of Vol. I but a fine and large set. C.W. Turner (University of Keele) bookplate.