Was hoping to send him some positive paper, but has been unable to prepare this due to a medical problem. Did make a sheet or two today. Returns some of the specimens JH sent him but would like to keep those made by JH himself.

Is grateful for the specimens sent him. Has been carrying out a series of experiments on the Calotype process with extraordinary results, especially the crimson skies. What does he think of the idea of publishing a treatise on 'Light' considered as a chemical agent?

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.

Was very pleased with the specimen JH sent him; it is still in good condition. Has he read [John William] Draper's paper? Comments on some of the points. Outlines some of his own proposed experiments.

Much indebted for his paper on the influence of the solar spectrum on vegetable colors. Has a series of experiments ready that he hopes will resolve some of his own doubts. Does not like the term J. W. Draper uses for the new rays.

Sends a few samples of plates made by the cyanotype process; they are poor because the sun has not been very strong of late. Comments on this process and wishes JH would make a few experiments with his more perfect apparatus. Inclined to agree with him about the mechanism of the eye.