This late 19th century example can be seen in the Maw catalogue (see picture) and was referred to as the ‘Incorrodible’ perhaps because of the silver plating.
It is a beautifully constructed mask made from fine silk overlying two perforated silver plated metal sheets. It is padded around the circumference with velvet lining. Two woven silk threads hold the mask in position behind the head and join each side through a pair of small gold coloured rosettes.
The respirator was first invented by Julius Jeffreys, a fellow of the Royal College of Surgeons in 1835. It was intended to warm inhaled air by passing it through a series of fine metal grids and to protect invalids from inhaling cold dry air. This design was later use by Snow in 1847 who used temperature to control the dosage of administered ether.