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Showing 1–20 of 22 items
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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.
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.
Compares actinometric measurements of radiation. Explains interest in total eclipse relative to actinometry. Discusses the possibility of making actinometric measurements by photographic means.
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.
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.
Instructions for preparing liquid for the actinometer. Describes 'very strange' experiments on the spectrum as well as an 'unusual' cloud formation.
Requests papers relative to a preface to the catalogue of [N. L.] Lacaille's stars, so that the catalogue may be printed.
Believes JH expressed support for pension for surviving child of Thomas Henderson. Comments on this, stating his own view that she is already well provided for.
Thanks for medal of the Royal Society of Edinburgh.
Comments on JH's Treatise Astr. in the Cabinet Cyclopaedia, mentioning its continued publication, misstatements he wishes to correct, and his addition of A. de Gasparis's newly-discovered planet [Hygeia].
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.'
Sets up approximate meeting time, depending on his family's timely departure to Antwerp, with JF at the R.S.L. apartments.
Requests information about actinometers in JF's possession, and provides further information regarding their use.
Believes all actinometric measurements made are useless because they did not take into account the rate of expansion of the liquid, which is not constant.
Thanks JF for second edition of work on the Alps. Praises first edition.
On the preparation of paper to exhibit a thermal spectrum.
Hopes to add JF's name to B.A.A.S. Meteorological Committee, and to see JF at Cambridge meeting of the committee.
[Responding to JF's 1849-11-23], JH cautiously discusses various considerations bearing on the idea of sending an astronomer and a large reflecting telescope to the Cape.
Protesting about the refusal of the Royal Society of Edinburgh to publish Thomas Brisbane's magnetic observations; hopes it will be reconsidered. Thinks JF's theory on glaciers has good points, but comments on some of its shortcomings.