Together 5¼ pages, 2o, lined paper, some light soiling. With: a large chart drawn in pencil by Becquerel of wavelengths of metallic vapors." /> BECQUEREL, Henri. Autograph manuscript signed, two drafts for his essay "Spectres d'emission infra-rouges des vapeurs métalliques," [Paris, 1884]. <I>Together 5¼ pages, 2<V>o, lined paper, some light soiling</I>. With: a large chart drawn in pencil by Becquerel of wavelengths of metallic vapors. | Christie's