Charles Wheatstone to Faraday   26 January 1853

Lower Mall | Hammersmith | Jany 26th 1853

My dear Faraday

If you will send to King’s College Dr Miller¹ will let you have the original revolving mirror with the whirling table to which it is fitted; I have spoken to him about it. I have at home a small revolving mirror (1/4 of an inch square) with a watch movement making 200 revolutions per second with a tolerably accurate means of measuring the angular elongation of a spark, which I have used to measure the duration of sparks in electro-magnetic coils; Mr Stokes can also have this if it will be of any service to him².

Yours very truly | C. Wheatstone