January 11th, 1855
I had the pleasure of sending you an invitation to our Soirées for the present season. The next will be on Wednesday the 17th. Are there any of your photographic productions, results of experiment, or Apparatus, which you would like to exhibit on that occasion? We record all objects exhibited, while the contribution of them confers at once a benefit and an obligation on the Institution. I will send for and return whatever you may like to contribute. Wednesday itself, of course, will not be too late, but it is more convenient to receive the Contributions on the Tuesday.
May I ask if you have read Power’s paper in Phil. Trans. (1854, Part I) entitled “Theory of the Reciprocal Action between the Solar Rays and the different media by which they are reflected, refracted, or absorbed; ” &c. in which the principle of harmonic resonance is, I think for the first time, applied to Optics. It appears to me to be a valuable contribution not merely to the Undulatory theory of Light, but to the universal theory of undulations in whatever medium excited, whether solid, liquid, ceriform, or etherial.
I remain, Dear Sir Very truly Yours
E. W. Brayley.
P.S. I intended to add but omitted it, that Power’s researches, in addition to Professor Stokes’s, seems to be important also as bearing on the subject of the great probability, not to use a stronger term, that the entire radiation of the Sun is really light, however it may be converted into heat and the chemical rays by the action of the atmosphere and the earth upon it, or however, but that action, those principles may be evolved from it. Herschel has always called the entire solar radiation light.
H. Fox Talbot Esq. F. R. S.