13 Great Stuart Street <1> Edinburgh
April 5th 1867
My Dear Sir
I am very much obliged to You for the indication of Mr Clerk Maxwell’s 2 papers <2> – I have looked at both of them – I made a good many expts on the subject in 1833, <3> starting from the Known fact that blue & yellow do not make green when successively presented to the eye on a rotating disk.
When sunlight is reflected from yellow paper upon blue paper, it makes green but when the image of the blue is thrown on the Yellow by a double refracting prism, it does not make green – There are various other anomalies –
H. F. Talbot
[on verso, in J D Forbes’s hand:]
Mr Fox Talbot
Clerk Maxwells colour Expts
1. 13 Great Stuart Street, Edinburgh, frequent home of the Talbots from 1863-1871.
3. WHFT, ‘Experiments on Light', London and Edinburgh Philosophical Magazine and Journal of Science, s. 3 v. 5 no. 29, November 1834, pp. 321-334. There is only one known surviving example of WHFT's Colour Revolving Photometer, made around 1835 for an American collector, which is now in the National Museums of Scotland. See Alison Morrison-Low and Allen Simpson, 'A New Dimension: A Context for Photography before 1860,' Light from the Dark Room (Edinburgh: National Galleries of Scotland, 1995), pp. 20-21.