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.

Willingly gives JH permission to engrave a portrait photograph taken with WT's process. WT asks JH if he would be willing to testify on WT's behalf if necessary, relating to infringement of patent rights. WT announces that John Hind has discovered another asteroid [Euterpe].

Asks JH to sign an affidavit that WT is the inventor of the calotype or talbotype as some are trying to break WT's patent hold.

Sends JH a copy of the affidavit [see WT's 1854-5-15] and asks for JH's emendations, if any, and his signature. Sends JH a photograph engraved on steel.

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.

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.

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.