Questions JH's intent to display 'photogenic drawings' to R.S.L.
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Questions JH's intent to display 'photogenic drawings' to R.S.L.
Enlarges upon his method of using salt as photographic fixer; then asks JH to explain the chemistry thereof. Has tried Louis Daguerre's fixing process without success.
Further chemicals used for fixing, including bromide potash.
Comments on Louis Daguerre's use of muriatic ether, and encloses a photograph of hand writing.
Comments on a number of chemicals used in photography, as well as referring to JH's process of making 'enlargements.'
Consists mostly of a transcription of two short notes from J. B. Biot to JH by way of WT.
Sends a sample picture fixed by use of iodine [potash].
More photography comments. Problems with use of hyposulfite fixer. Superiority of English over Daguerreotype in being able to make copies.
Confused by an 'unfixed' photo from JH in which the image shows different effects from different colors of the spectrum. Also other comments on photography.
Sends JH a positive copy and a transparency. Remarks on JH's use of muriate of lead and asks JH to explain chemistry of it.
Advises JH not to publish any new processes in photography as there are patent problems. Comments on the Daguerreotype, and on the difficulty of preserving images in some circumstances.
Sends some samples of photography made with a solar microscope, and comments briefly on the Daguerreotype.
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.'
Considerable comment on procedure for submitting paper to R.S.L. Urges WT to mention JH's method of washing with hyposulfite. Comments on some photographic experiments of WT.
Thanks for specimen of light sensitive paper. Provides hint on the chemical process that Louis Daguerre may have used in his photographic work. Sends specimens of JH's own work.
Describes method of varying the size of photographic images. Praises Talbot's light sensitive paper and suggests improvements regarding it. Complains about persons too ready to seek a patent.
Sending WT some seeds. Had hoped to send some bulbs.
Is sending WT some botanical specimens through Andrew Smith, whose scientific abilities JH praises. Asks WT to assist Smith in England. Encourages WT's work in mathematics and in 'photology.' Reports on JH's astronomical observations and theorizes about sunspots.
Says that for the next four to five months will be in residence at 10 Hanover Crescent, Regent's Park. Offers various botanical specimens to WT, including a Satyrium named after JH. Mentions Eta Argus. Believes the 'Southern Sky has been pretty well rummaged.'
[Responding to WT's 1839-1-25], JH reports that he cannot come to London to see WT's 'curious process of fixing the image formed by a Camera obscura.' Invites WT to come to Slough.