Autograph Letter Signed, to Monsieur Boutigny [Pierre Hippolyte Boutigny, professor of chemistry], commenting on his work on “l’état sphéroidal”, discussing with enthusiasm his own experiments with flying machines, and mentioning an experiment with carbonic acid. In French. 3 pp. 8 x 5 inches, with address leaf (tipped on to part album page), in good condition. Laboratoire de Ed. Moride, Nantes, 11 May 1850. Edouard Moride, French chemist.