Comments on JD's work in photography; JH goes on to talk about JH's ideas of 'chemical' rays of light.
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Comments on JD's work in photography; JH goes on to talk about JH's ideas of 'chemical' rays of light.
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.
Sends CW a specimen of JH's 'mercurial photographic process.' JH is pleased that W. H. Fox Talbot received the Rumford medal.
Is anxious for some means to be developed to get a measurable quantity [preferably by weight] from the action of a beam of light on a surface. JH has been experimenting in photography with 'flouric' compounds.
Sending, care of Dr. Grant, the first part of a series of experiments on the magnetic influence of light, which appeared recently in the Calcutta Journal. Has been unable to obtain a characteristic specimen of Kankar in Bengal. Dr. Hugh Falconer is an expert on the Kankar in Bengal and he will try to obtain information from Falconer.
Sends description and drawings of JH's actinoscope. Requests estimate for time and expense of constructing it. Questions about clock mechanism and prisms.
Regrets that GD cannot build JH's entire actinoscope. If GD can make at least mechanical components, JH will supply optics and clockwork. Can GD complete these [by end of March]? Funds are limited; please estimate cost.
Confirms scale of drawings [for JH's actinoscope]. Has found simple contrivance to replace clockwork. Will order lenses and prisms from Munich; all English glass has color aberrations.
Papers arrived safely. Will report GD's opinion on these soon.
Sees too many difficulties in optics of JH's proposed telescope. Can build mechanical portion, but not by March as JH requires. Cannot give estimate, because design is too novel.
Will begin building components that JH identified as most immediately needed. Confirm scale of JH's drawings. Will send samples of prism glass for JH to inspect. Cannot yet estimate cost.
About chemical solutions used in photography, and problems produced by impurities in photographic paper.
Thanks JH for a specimen of 'mercury type,' which AS describes as he examined it under a microscope.
Thanks JH for the poem [JH's translation of Friedrich Schiller's 'The Walk'] he sent. Requests a song sung by 'faery elves' in William Herschel's telescope.
Finished the reductions of all of the nebulae and double stars recorded at Cape Town; JH soon hopes to prepare for the publication of his Cape Results.
Thanks JH for JH's translation of Friederich Schiller's poem 'The Walk.'
Sends RH a packet of photographs with a description of each type.
Read John William Draper's papers; although he believes that Draper's instruments are inconsistent, JH feels that they are still important because they are measurable. Decries [L. F.] Moser's skepticism of photography's value, calling it a 'blindfolding to some of the most interesting physical relations that have ever been discovered.'