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Document number: 04428
Date: 01 Feb 1842
Recipient: TALBOT William Henry Fox
Author: RYAN John
Collection: British Library, London, Manuscripts - Fox Talbot Collection
Collection number historic: LA42-7
Last updated: 28th January 2015

16 Orchard St. Portman Square
Feby 1st/42.


I have been busily engaged in a series of careful experiments with the Calotype, during the past fortnight, and am now ready to commence my lectures on that subject. <1>

Prior, however, to my doing so, I request your written views of the mode in which the lectures ought to be arranged, and of the points which should be most prominently introduced. I beg, too, as a favour, that if there be in your possession any practical hints on the subject, unpublished, in your specification, I may be made acquainted with them as soon as possible.

Owing to the state of the weather, we have not been able to employ the Camera. Our experiments have been confined to the microscope: using of course the Hydro Oxygen Light. We have in the affair followed your instructions step by step.

At present I propose to introduce the following items into my lectures:

General views of the Philosophy of picture-taking by Light, whether by your method or by that of others.

The rationale of the action of light on certain chemical compounds, such as Nitrate Silver &c.

The History of your discovery: a minute explanation of the steps of the process, during the preparation of the paper, and the mode of employing it in the Camera, or microscope.

Of course I shall accompany every step by actual experiment.

If you desire anything more, or any change in the arrangement of the subject, I should feel obliged by your writing to me as soon as you conveniently can.

I remain yours &c
John Ryan [illegible]

H. F. Talbot Esqre.

H. F. Talbot Esqre
Lacock Abbey


1. The lectures on 'Mr Fox Talbot's Calotype Process' were delayed until July when the Royal Polytechnic Institution's new rooms onto Cavendish Square were opened - they met with great success. Undoubtedly some visitors also came to see Richard Beard's Daguerreotype studio, based there. See Doc. No: 04457. Dr. Ryan regularly lectured on a varity of chemical subjects and published "Hints on a New Theory of the Phenomena of the Daguerreotype," The Polytechnic Journal; a Magazine of Art and Science, v. 6 no. 3, March 1842, pp. 129-132.