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Document number: 2625
Date: 04 Mar 1833
Recipient: HERSCHEL John Frederick William
Author: TALBOT William Henry Fox
Collection: Royal Society, London
Collection number: HS 17:268
Last updated: 30th April 2012

31 Sackville St London <1>
4th March 1833

Dear Sir

I have read in the newspapers that you are going to the Cape of Good Hope, and am desirous to know whether the rumour be true.

I saw a very pretty experiment last Friday at the Royal Institution <2> by which it is demonstrated that the Electric spark is never continuous, however close the bodies are between which the sparks pass; but that on the contrary Galvanic electricity gives a continuous discharge.

This has brought to my mind a train of experiments which I formerly executed, attended with interesting results, one of which astonished me much when I first beheld it. It is a method of rendering the image of a body which is in the most rapid motion entirely fixed, so that you can see what happens to it under such circumstances with as much ease as if it were at rest. And I contrived a Photometer <3> upon principles I consider perfectly accurate. I wish therefore to ask you if you think that any Photometer has been described that is quite free from objection?

I don’t know why I have suffered these experiments to slumber in my portfolio for seven years; but I am now thinking of presenting them in the form of a short paper to the Royal Society. <4>

Believe me Dear Sir With great regard Yours truly
H. F. Talbot


Notes:

1. 31 Sackville Street, London residence of the Feildings, often used as a London base by WHFT.

2. Sir Charles Wheatstone (1802–1875), scientist, gave a series of lectures on Friday afternoons at the Royal Institution, London. The following week, Friday, 8 March, WHFT recorded in his pocketbook, ‘“Wheatstone on Light” at Royal Institution’. [See WHFT memoranda notebook in the Fox Talbot Collection, the British Library].

3. Any instrument that measures the relative intensity, or ‘candle power’ of light would be considered a photometer, but many of them were not satisfactory.

4. WHFT, ‘Proposed Philosophical Experiments’, Philosophical Magazine, v. 3, August 1833, pp.81–82.