Coates' modification of Snow type inhaler for chloroform anaesthesia, made by William Matthews, Carey Street, London, England, 1854-1880

Inside the spherical brass container are air holes, to vapourise the liquid chloroform. A patient would inhale the chloroform through the rubber mask which has inhaling and exhaling valves. It is likely that Coates refers to William Martin Coates, a surgeon at Salisbury Infirmiary who was carying out experiments on chloroform. In his writings, he describes using a Snow type chloroform inhaler for his patients.