Electro-magnetism.- Ampère (André Marie) and Jacques Babinet. Exposé des Nouvelles Découvertes sur l'Electricité et le Magnétisme, first edition, offprint, half-title, illustrations, foxing, later wrappers, lower cover with closed tear repaired, [COPAC lists BL, Oxford and Science Museum only], 8vo, Paris, Chez Mequignon-Marvis, 1822.

⁂ Rare offprint from the Supplement to the French translation of Thomas Thompson's System of Chemistry. It was in this work that Ampère (1775-1836) first introduced (pp. 26-27) his famous rule for determining the direction of deviation of a magnetic needle placed near an electric current (the rule was stated by Oersted in an obscure Danish publication in the same year).