Signedon spout: GAZOGENE / BRIET / BREVETÉ, S.G.D.G [faded]; on stopcock: BRIET / BTÉ S.G.D.C. / PARIS
FunctionFrom ad (see primary sources): "Soda water apparatus (with metal or improved glass tube) for the immediate production of Soda-water, Lemonade, Sparkling Wine etc. etc. The delightful beverages made with the Gazogene renders it an almost necessary requisite for the dinner table, while its extensive introduction into most of the French and many of the English Hospitals is a guarantee of its value in the sick chamber."
Primary SourcesAn advertisement of this device can be found in; Medical Times and Gazette, Vol. 10 (1855), p. 612. Available online in Google Books here.