The small volume of which we have spoken is devoted more particularly to electric navigation, for which M. Trouvé specially designed the motor of his invention, and by the aid of which he performed numerous experiments on the ocean, on the Seine at Paris, and before Rouen and at Troyes. In this latter case M. Trouvé gained a medal of honor on the occasion of a regatta. Our engraving represents him competing with the rowers of whom he kept ahead with so distinguished success. We could not undertake to enumerate all the inventions which we owe to M. Trouvé; but we cannot, however, omit mention of the pendulum escapement that beats the second or half second without any variation in the length of the balance; of the electric gyroscope constructed at the request of M. Louis Foucault; of the electro-medical pocket-case; of the apparatus for determining the most advantageous inclination to give a helix; of the electric bit for stopping unruly horses; and of the universal caustic-holder. He has given the electric polyscope features such that every cavity in the human body may be explored by its aid. As for his electric motor, he has given that a form that makes the rotation regular and suppresses dead-centers--a result that he has obtained by utilizing the eccentrization of the Siemens bobbin. Although devoting himself mainly to improving his motor (which, by the way, he has applied to the tricycle), M. Trouvé does not disdain telephony, but has introduced into the manufacture of magnets for the purpose many valuable improvements.--_Electricité_. [Illustration: TROUVE'S ELECTRIC BOAT COMPETING IN THE REGATTA AT TROYES, AUG. 6, 1882.] * * * * * FRIEDRICH WÖHLER. At the age of eighty-two years, and full of honor, after a life actively devoted to scientific work of the highest and most accurate kind, which has contributed more than that of any other contemporary to establish the principles on which an exact science like chemistry is founded, the illustrious Wöhler has gone to his rest. After he had worked for some time with Berzelius in Sweden, he taught chemistry from 1825 to 1831 at the Polytechnic School in Berlin; then till 1836 he was stationed at the Higher Polytechnic School at Cassel, and then he became Ordinary Professor of Chemistry in the University of Göttingen, where he remained till his death. He was born, July 31, 1800, at Eschersheim, near Frankfort-on-the-Main.