2. Bruxelles, Hayez, Imprimeur, 1869, in-8°, article of ca. 20 pp published in the ''Bulletin de L'Académie Royale des Sciences'' Year 1869, issue 4. Here the complete issue is on offer. Sewn, with original wrapper. (Front wrapper is missing, margins are frayed and dustsoiled, unopened copy - not a nice copy).