link to Talbot Project home page link to De Montfort University home page link to Glasgow University home page
Project Director: Professor Larry J Schaaf

Back to the letter search >

Document number: 04433
Date: 16 Feb 1842
Recipient: TALBOT William Henry Fox
Author: WHEATSTONE Charles
Collection: British Library, London, Manuscripts - Fox Talbot Collection
Collection number historic: LA42-010
Last updated: 1st September 2003

20 Conduit St

Feby 16th 1842

My dear Sir

Since I last wrote to you I have been absent from town and therefore little has been done since the enrollment of the specification. <1> On my return I found the model of the eccentric engine made as I originally directed, had been sent home by Henly, <2> and I have devoted a day or two to experiments with it; it has exceeded my expectations, and considering its size and the consumption of material it is no doubt the most effective engine that has ever been made. With a common trough battery of 10 elements the fly wheel makes about 1500 revolutions per minute, and it works tolerably rapid with 3 only; this is very encouraging when it is considered that only one small electro-magnet (not larger than one of my telegraph magnets) is active at the same time. A great improvement has occurred to me by which I shall be able to bring one half the number of electro-magnets into simultaneous action (8 is the present number) and thus quadruple the effective power of the engine by using a battery of the same number of plates but larger. The same improvement is applicable to the disc engine. I have also devised a very simple means of totally obviating the spark and the consequent oxidation of the rheotome <3> which is the cause of so much annoyance.

I am anxious to know when you will return to town, in order that we may consult respecting what shall be next proceeded with. I received a letter yesterday which may oblige me to go to Brussells for a month; I shall however endeavour to put off this journey till the summer as I have many things besides the one in which we are mutually interested, which at present require my constant attention at home.

Yours very truly

C. Wheatstone.

H. F. Talbot Esqr
Lacock Abbey
nr Chippenham


1. See Doc. No: 04421.

2. William Thomas Henley (1814–1882), instrument maker.

3. A device for interrupting the electric current.