Collingwood ^<1>
May 14/41

My dear sir

Among a vast N^o of trials I have been lately making on vegetable juices I have lighted upon one of a very singular character – quite contrary to the analogy of all the rest except [illegible deletion]. I send you a specimen (N^o 1040) ^<2> in which A is the original colour of the paper before exposure to light & B that assumed after long exposure. The intermediate portion has been subjected to the action of the spectrum. The scale VYR at the side shews the extent of the luminous spectrum exclusive of the sun’s diameter – and you will observe that the Red rays have no effect the yellow scarce perceptible the Indigo-blue the maximum and that the action extends far beyond the luminous spectrum. In a word the resemblance is great to the spectral-impression on paper prepared with the Nitrate of Silver and Hydriod. of Potash – and it agrees with the argentine spect^m in being darker than the ground colour and in the tone of tint.

I have been so very unlucky as to lose your paper about the Calotype. ^<3> I believe I lent it & it has not been returned – have you still one to spare?

Believe me Dear sir Yours very truly
JFW Herschel

PS. The juice is that of a Cape plant I brought home with me I believe a new species of Anthericum. I have only a single growing specimen & am very unwilling to destroy it and as it is but a small plant it is with difficulty I collected by bleeding enough juice to colour this paper – I shall therefore beg the favor of you to reinclose it at your leisure. PS I enclose ^<4> another spect^m on yellow paper N^o 1042 which exhibits a curious contrast with N^o 1040. It has just turned up.

Most yellow juices I have hitherto tried have proved nearly insensible This on the contrary is very sensible – the spectrum annexed was impressed in 55 minutes.

H. F. Talbot Esq^r
Lacock Abbey
Chippenham
Wilts
31 Sackville Street ^<5>
London

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Notes:

1. The Herschel family home in Hawkhurst, Kent.

2. Unlike WHFT, whose research had a much more random character, Herschel established regularly-numbered series of photographic experiments. These are detailed in various research notebooks, now held by the Sceince Museum Library, London. The two major published records are Herschel’s ‘On the Chemical Action of the Rays of the Solar Spectrum on Preparations of Silver and Other Substances, Both Metallic and Non-metallic, and on Some Photographic Processes,’ Philosophical Transactions of the Royal Society of London, 1840, pp. 1–59; ‘On the action of the Rays of the Solar Spectrum on Vegetable Colours, and on some new Photographic Processes’ (read 16 June 1842, postscript added 29 August 1842), v.132, 1842, pp.181–214. Examples of these spectra are illustrated as plate 8 in Larry J. Schaaf, Out of the Shadows (London: Yale University Press, 1992) p. 125.

3. Either ‘Calotype (Photogenic) Drawing’, The Literary Gazette and Journal of belles lettres, science and art, no. 1256, 13 February 1841, p. 108; or ‘Fine Arts: Calotype (Photogenic) Drawing’, The Literary Gazette and Journal of belles lettres, science and art, n.1258, 27 February 1841, pp. 139–140. In Doc. No: 04213, Herschel acknowledged receipt of what he called a ‘circular’, on the subject.

4. Enclosures not located.

5. 31 Sackville Street, London residence of the Feildings, often used as a London base by WHFT.