Pyrometer by Henry Hindley, c.1750
Hindley was an expert instrument maker whom Demainbray met in York. This pyrometer, a device for showing the thermal expansion of different metals, was made by Hindley to a design either by himself or by Demainbray. A metal bar is placed along the base and heated by a row of lighted wicks in an oil bath. As the bar expands, it pushes an arm which turns the pointer on the dial at the top. This pyrometer is one of the pieces of Demainbray's apparatus that can be identified from notes made at Demainbray's lectures in Bordeaux by one Père Chabrol.
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