Comments on several experiments with spectra passing through glass films.
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Comments on several experiments with spectra passing through glass films.
Asks JH about Dr. Balfour's account in Asiatic Researches about lunar effects on humans in India.
Comments on use of muriate of lime on plants. Also on existence of unexplained bands on film and on presence of red light beyond normal spectrum with light originating from certain sources.
Questions and comments regarding improvements in microscopy.
Comments on Josef Fraunhofer's work on double stars, on quality and color of light from different sources, refraction of different kinds of light, and solution of a problem in conic sections. Is going to Geneva and Modena soon.
Describes observations made as he travelled and people visited on journey from London to Ancona.
Talks about Josef Fraunhofer's failing health and his making of flint glass.
Is sending on two items directed to JH through WT.
Describes prismatic spectrum of flame of cyanogen and offers to repeat experiment with Michael Faraday for JH's benefit.
Asks JH to clarify what goods are his from a joint order with WT from a German optical firm.
Queries and comments about telescopes and microscopes; some thoughts about a diffraction grating.
Renders an accounting of expenses for optical goods received from Germany.
Writes in favour of a London University professorship for Thomas Key. Refers to some optical experiments of Michael Faraday, and extends solution of conic section problem first raised in WT's letter of 1826-2-27.
Asks about rumor regarding JH going to Cape. Describes some electrical experiments WT saw at Royal Institution and refers to some WT carried out years earlier.
Asks for seeds and roots of native plants of the Cape. Refers to JH's writings on beating of the heart and comments on some optical experiments of Charles Wheatstone and David Brewster.
Comments on JH's paper on potash in Annales de chimie. Has observed reaction products in microscope. Concerned over delay in publication by David Brewster of his experimental results in optics and light, especially as WT not convinced of legitimacy of rumored results.
Has performed some Newton's rings interference experiments. Asks whether such experiments have already been communicated to the R.S.L.
Trying to understand David Brewster's results on absorption of light in gaseous state, and the dark lines in solar spectrum, the cause of which he misunderstands.
About plant seeds sent by JH from the Cape, WT having sent him some Mexican seeds in return. Halley's Comet only clearly seen on two nights.
Writing to welcome JH home from the Cape.