Francois-Frauck double manometer on brass stand, used with Marey chronograph to study blood pressure at d'Arsonval laboratory, by Charles Verdin, French, 7 rue Linne, Paris, France, 1851-1900. Francois-Frauck double manometer on brass stand Laboratory Medicine 1851-1900
Mercury sphygmomanometer, manometer only, in wooden case, by Hawkesley and Son, 357 Oxford Street, London, England, 1890-1930. Mercury sphygmomanometer Clinical Diagnosis 1890-1930
