Has been working at [L. F.] Moser's experiments and believes he is wrong in considering latent light as the agent that produces the photographic image. Read a paper last evening on the subject, which will be printed. Has been producing images by the action of heat and electricity and proposes to call this process Thermography.

Was pleased to receive JH's letter and to read that he had really proved the existence of [invisible light?]. One of his students has produced images on copper plates by sulfur fumes. Has just seen Macedoine Melloni's memoir, which is now governed by JH's views.