20 Conduit St
Jany 9th 1842
My dear Sir
The specification <1> was duly enrolled on Friday last. The only material alteration I have made in it with which you are not acquainted, is the substitution of a new form of the tangential engine for the one I had first intended to specify; by this change no resemblance to Mr Petries’ <2> machine remains and I have been enabled to claim the principle on which its construction depends in a much more general manner. I think this new form of electro-magnetic engine will give some valuable results. The cash you last gave me on account has been wholly consumed for the specification, stamps &c. and I shall therefore suspend further operations untill we have an opportunity of consulting together to determine which of the objects it will be most expedient to follow out immediately.
Yours very truly
C. Wheatstone.
<H.> F. Talbot Esqre
Lacock Abbey
Chippenham
Wilts
Notes:
1. See Doc. No: 04433.
2. William Petrie took out the first of his several patents on obtaining motive power on 19 June 1841, patent number 8937.