Liége, J. Desoer, 1867. 8vo (22.5 x 14.3 cm). 352 pp. 20th-century half cloth over reptile-skin boards. Original printed wrappers bound in.

A rare work. It combines 79 mathematical works by the French-Belgian mathematician Eugène Charles Catalan (1814-1894) which were published earlier, but appear here, reviewed by the author and with new additions (all dated). Included are works on number theory, the calculus of numbers by Bernouilli, comments on a work by Poisson, a work on Fermat's theorem, and on works by Newton and by Euler. Catalan "...worked on continued fractions, descriptive geometry, number theory and combinatorics. His notable contributions included discovering a periodic minimal surface in the space R3; stating the famous Catalan's conjecture, which was eventually proved in 2002; and introducing the Catalan numbers to solve a combinatorial problem" (Wikipedia). Two papers (the one numbered 15, and a comment, from a letter, to the same) are by the French professor of mathematics, Charles Pierre Housel (1817-1874). Offprint from the Mémoires de la Société royale des Sciences de Liége, Deuxième Série, Volume 2. Blind stamp on title; short tear in the margin of pp. 45-48; otherwise very good, clean.