Tells WT about JH developing the thermographic paper which is susceptible to 'calorific' and 'chemical' rays of light.
Tells WT about JH developing the thermographic paper which is susceptible to 'calorific' and 'chemical' rays of light.
Waited until after 14 Feb. to submit JH's paper on photography ['On the Chemical Action of the Rays of the Solar Spectrum...,' R.S.P.T. (1840), 1-59]. Will send WT a copy.
Sending specimens sent to JH by [Robert] Hunt. Praises Hunt. Has WT received JH's paper ['On the Chemical Action of the Rays of the Solar Spectrum...,' R.S.P.T. (1840), 1-59]? JH moving to Collingwood.
Thanks for excellent pictures WT sent. JH wishes JH had time for further experiments, especially on the 'thermic spectrum.' Praises [Robert] Hunt's results. Recommends experiment to WT.
Praises various photographs by WT and notes changes in some. Recounts optical experiments, recent and planned, by JH on rock-salt.
Sends WT a copy of the solar spectrum in which each color is represented clearly in a 'positive' picture. JH sees this as giving hope for color photography.