Outlines theory behind and method for preparing thermographic paper, which allows observers to determine 'what share each ray of the spectrum bears in producing the observed total effects.'
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Outlines theory behind and method for preparing thermographic paper, which allows observers to determine 'what share each ray of the spectrum bears in producing the observed total effects.'
Would like to know the degree of sensibility to heat of JH's paper. The paper of W. H. F. Talbot is useless for his purpose as only violet heat affects it. Did JH use a flint glass prism for his spectrum experiments? Has he ever used photography to show the impression of polarization and diffraction?
On the preparation of paper to exhibit a thermal spectrum.
No summary available.
Explains results obtained by R.S.L. subcommittee considering state of meteorological journal published in R.S.P.T. Wonders about feasibility of establishing 'simple but accurate meteorological register' under public authority.
R.S.L. will deviate from its intellectual purpose whenever it meddles in practical observations. Proper role for R.S.L. is to suggest goals and methods and to reward discoveries. Recommends discontinuing meteorological observations at Somerset House; other stations now provide better data. If R.S.L. insists on establishing a meteorological register, JH suggests one like that of J. F. Daniell.
Describes difficulties in attempting to produce good meteorological register and establish national meteorological observatory.
Explains efforts at using a makeshift apparatus for 'fixing the spectrum.' Discusses current confusion and ultimate hope surrounding JF's meteorological recommendations. In a postscript, notes observations of meteors in Persei.
Thanks for JH's letters and the paper on photography with special reference to the effects of heat. Was present at the R.S.L. during consideration of a national observatory. Would like JH's opinion. Is working on a supplementary report on meteorology.
Sending a notice about the polarization of the sky. Also some practical papers he set at Durham. Has the obelisk ready for shipment to the Cape. Has asked Richard Taylor to send him a copy of his report on Meteorology.
About various testimonials, from JH and others, for JF's application for a government pension.
Is grateful for JH's letter and commendation regarding application for a government pension; will endeavor to carry out his recommendations.
Would like to know the composition of the fluid in JH's actinometers.
Instructions for preparing liquid for the actinometer. Describes 'very strange' experiments on the spectrum as well as an 'unusual' cloud formation.
Proposes meeting times in town. Suggests that JF observe the upcoming total eclipse astronomically. Agrees with JF's seemingly 'cold &c' circular on scientific partnerships, while regretting that it needed to be written.
Would like to see him for a few minutes to discuss a paper he is preparing for the R.S.L. on actinometer observations.
No meeting of the R.S.L. on the 19th but could arrange to see him before dinner. Hopes to spend the summer amongst the glaciers.
Sets up approximate meeting time, depending on his family's timely departure to Antwerp, with JF at the R.S.L. apartments.
Compares actinometric measurements of radiation. Explains interest in total eclipse relative to actinometry. Discusses the possibility of making actinometric measurements by photographic means.
Received JF's paper on 'thermographic process.' Believes that thermic rays were responsible for experimental results of JF, J. W. Draper, and Ludwig Moser. JH's theory of and experiments with thermic rays, which are different from 'calorific' and visible rays, in solar spectrum.