Tells WT about JH developing the thermographic paper which is susceptible to 'calorific' and 'chemical' rays of light.
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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.