Mentions RH’s book on light [Researches on light in its chemical relations, 2d ed. (1854)]. Asks about coloured glass used in experiments on plants.
Mentions RH’s book on light [Researches on light in its chemical relations, 2d ed. (1854)]. Asks about coloured glass used in experiments on plants.
Mentions experiments on plants involving coloured glass. Encloses correspondence from glass maker and asks advice.
Encloses a sketch of the principal events in his life [for RH’s memoir on CD in Walford, ed., Portraits of men of eminence (1863–7)].
No summary available.
No summary available.
No summary available.
Intrigued by RH's experiments with photographic papers; will buy six sheets of RH's specimens. Admits having conducted numerous experiments himself and asks to include some of RH's results in a forthcoming paper on the subject.
Hopes that his paper does not anticipate any of RH's work; will share with the R.S.L. any of RH's results. Laments that he is unable to fix the spectral colors on photographic paper. Asks if RH has studied the bromines.
Exchanging further information on several aspects of the photographic process [see RH's 1840-4-15].
Will forward RH's paper to the R.S.L.; intrigued by RH's results using mercury vapor to produce the image on exposed paper.
Thanks RH for a sample of Daguerreotype paper. Comments on some aspects of the action of 'thermic' rays and 'chemical' rays in photography.
Does not know anywhere that such processes as RH uses are used for registry work, although the idea is frequently raised.
Has not lately done much work in photography, except to work with paper treated with vegetable substances.
Unable to give any specifics concerning Louis Jacques Mandé Daguerre's new photographic process. Discovered that old paper specimens produced a much better representation of the spectrum in its natural colors than those obtained at the date of JH's paper; these results are 'light on a dark ground,' which makes JH more hopeful that colored photography will someday be perfected. Has experimented with vegetable substances.
Thanks RH for his 'extensive and instructive view on the present state of photography.' Found many interesting results in experimenting with vegetable substances. Surprised by RH's discovery that bi-chromate of potash is a photographic substance; JH nearly achieved this result.
Believes that the operative rays in JH's thermographic process are neither 'calorific' nor 'thermal'.
Some information about Charles Piazzi Smyth. JH needs information about some of RH's photographic paper, which JH has tried but without success.
Sorry to hear RH has been ill; JH sends some photographic examples.
Thanks for RH's paper on mineralogy. JH has explored use of mercury together with iron in photography.
Sends RH a packet of photographs with a description of each type.