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Document number: 273
Date: 29 Jun 1836
Recipient: TALBOT William Henry Fox
Author: CHILDREN John George
Collection: British Library, London, Manuscripts - Fox Talbot Collection
Last updated: 5th December 2012

British Museum <1>
29th June – 1836.

My dear Sir,

The Council of the Royal Society, has desired me to communicate to you the report of the gentleman to whom your paper on the circular crystals <2> was referred – a copy of which I subjoin – I shall be glad to have any remarks you may wish to make on the report, before the next meeting of the Council, 7th July – I have got some of the glacial phosphoric acid, from Davy’s, <3> but have not yet had leisure to try it – was what you had of him of foreign manufacture?

Ever My dear Sir, faithfully your’s [sic]
J. G. Children

Copy of Report.

Mr Talbot’s paper contains curious facts; it is not clear whether they can or cannot be accounted for my means of the known laws of crystalline optics – His reasonings upon them appears to me unsatisfactory and wanting in distinctness. If the paper is printed I would offer the following suggestions.

The circular crystals spoken of p. 8 & 9 are not simple, but aggregate acicular crystals. Hence the mode of explaining the facts is by shewing that they result from the action of the separate spiculæ, and not by loose analogies, like those of spheres of glass, and lenses of fishes, p. 9. Nor is this mode of crystallization properly called “a form of crystallization” (Note p. 8) as if it were a simple form. Dichroism, p. 15 [illegible deletion] Nothing but confusion can, I think, result, from including the phenomena here described under the term dichroism, since they appear to be well-known phenomena of another kind, namely those produced by polarised light passing through crystals and then analysed, I think the word ought to be omitted.

I would also omit all such mention of the theory as is made in p. 20. We are not now at a point of the history of the undulatory theory, when such vague arguments as are there given can be spoken of as “much in favour” of the theory, or against it.

The notion of circular crystals in p. 21 I object to, for the reasons above mentioned in referring to the note p. 8.

Henry Fox Talbot Esqre
Lacock Abbey
Chippenham
Wilts


Notes:

1. London.

2. WHFT, ‘Observations on the Optical Phenomena of certain Crystals’, Philosophical Transactions of the Royal Society of London, v. 127 pt. 1, 1837; paper received 20 April, read 5 May 1836. [See Doc. No: 03305].

3. Sir Humphry Davy (1778–1829), chemist.

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