Flintmill, 18th century.
© Science Museum / Science & Society Picture Library
Flint and steel mill, designed by Carlisle Spedding (1696-1755). Light was obtained in the form of a stream of sparks created by rotating a thin steel disc against a flint. A letter was written about the mill in 1813 to the 'Society for Preventing Accidents in Coal Mines' in Sunderland and described it as '...an instrument for striking light with flint and steel. [sic] The bras wheels are placed in a light frame of iron which is suspended by a leather belt round the neck of the person who plays the mill. Great velocity is given to the steel wheel by turning the handle of the toothed wheel, and the sharp edge of a flint is applied to the circumference of the steel wheel, which immediately elicits an abundance of sparks, and emits considerable light.