Comments on the affidavit supplied by WT; will sign most of it but objects to one section.

Explains the way an affidavit works in the Court of Chancery. Because JH feels uncomfortable about certain aspects of the affidavit, WT will not trouble him about it again.

Clarifies JH's position, by saying that he clearly supports WT as the inventor of the calotype or talbotype, but has reservations about the collodion process.

WT's opponents have named JH in one of their affidavits against WT. WT is therefore asking JH to respond to what is stated in that affidavit.

Reports to JH that the patent infringement case had been decided in WT's favor, and tells of one incident in court.

Sent WT's specimens to J. B. Biot and F. J. D. Arago in Paris. Developed paper sensitive to heat rays of sun 'beyond the spectrum.' Diagram of three spectra: 'luminous, chemical, and thermic.'

Asks JH about Dr. Balfour's account in Asiatic Researches about lunar effects on humans in India.

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.

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.

Describes prismatic spectrum of flame of cyanogen and offers to repeat experiment with Michael Faraday for JH's benefit.

Queries and comments about telescopes and microscopes; some thoughts about a diffraction grating.

Asks JH to clarify what goods are his from a joint order with WT from a German optical firm.

Renders an accounting of expenses for optical goods received from Germany.

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.

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.

Has performed some Newton's rings interference experiments. Asks whether such experiments have already been communicated to the R.S.L.