Lacock Abbey, Chippenham
12 Janry 1843
Sir
Mr Watkins <1> having mentioned to me that you were going to give a lecture on the 10th Feb. at the R. Instn <2> on Electromagnetic Machines, <3> I take the liberty of addressing a few lines to you on the subject.
I have recently had an engine constructed, which I believe to be more powerful in proportion to its size than any hitherto made, and I should be happy to lend it to you for the occasion, only that it is now undergoing alteration and I doubt whether it will be ready in time – A previous attempt I made was not successful owing to the proportions being not well adjusted: but the present, from a preliminary trial, has considerable power. It is made on the principle for which I took a patent <4> two years ago, and the description with figures will be found in the Repertory of patent Inventions. Mr Davidson <5> is exhibiting a small engine on the same principle at the Egyptian Hall, <6> it is employed to work a small saw – The principle of my Engine consists in this, that the armature lies quiescent on the magnet during nearly half the time – or in other words, that when it strikes the magnet, the rest of the mass in motion is disengaged from it. Wheatstone’s excentric [sic] Engine <7> is a joint invention of Professor W. and myself, if it were worth while we could point out the share which each of us had in it – Practically speaking I think my own arrangement most likely to produce a real working engine –
I am Sir Your obedt Servt
H. Fox Talbot
Notes:
1. Francis Watkins, of Watkins & Hill, instrument makers, London. See his letter, Doc. No: 04693, of 10 January 1843.
2. Royal Institution, London.
3. Also, ‘magneto-electric’ engines.
4. Patent Number 8650, 1 October 1840, ‘Obtaining Motive Power’.
5. Robert Davidson, Scottish electrical inventor. [See Doc. No: 04686, Doc. No: 04696.]
6. In the Strand, London. [See Doc. No: 04658.]
7. Sir Charles Wheatstone (1802–1875), scientist. [See also Doc. No: 04421 and Doc. No: 04433].