Face mask and regulator from Hewitt's modification of Clover's Portable Regulating Ether Inhaler", regulator made by Holborn Surgical Instrument Co., London, 1877-1920 Face mask and regulator from Hewitt's modification of Clover's Portable Regulating Ether Inhaler" 1877-1920
Face mask and regulator from Clover's "Portable Regulating Ether Inhaler", made by Mayer and Meltzer of London, 1880-1920 Clover type Portable Regulating Inhaler 1880-1920