About chemical solutions used in photography, and problems produced by impurities in photographic paper.
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About chemical solutions used in photography, and problems produced by impurities in photographic paper.
Sends RH a packet of photographs with a description of each type.
Sends CW a specimen of JH's 'mercurial photographic process.' JH is pleased that W. H. Fox Talbot received the Rumford medal.
Comments on JD's work in photography; JH goes on to talk about JH's ideas of 'chemical' rays of light.
No summary available.
No summary available.
Orders large pot of spermaceti ointment.
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.
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.
CD likes Down House, describes countryside.
Tells of Edward Charlesworth fracas at Geological Society.
Is at work on Volcanic islands.
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.
Declines invitation.
Asks for advice on a number of scientific papers.
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.'
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 description and drawings of JH's actinoscope. Requests estimate for time and expense of constructing it. Questions about clock mechanism and prisms.
Papers arrived safely. Will report GD's opinion on these soon.
Thanks JH for a specimen of 'mercury type,' which AS describes as he examined it under a microscope.
Discusses matter touching P.M. and Scientific Memoirs.
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.