William Fothergill Cooke : biography
The cramped living quarters that Cooke was holed-up in is clearly spelled out in his candid letter to Mrs. Hawes. How much stress Cooke endured over the anxieties that surmounted him towards fulfilling his goal of the electric telegraph, and the expression of relief he gained once he knew he had successfully completed the negotiations to install his telegraph – are all expressed both succinctly and exuberantly in his historic 30 May 1838 letter to Mrs. Hawes! The fact that Cooke knew his room’s size down to "seven sixteenths" of an inch, is also truly remarkable. This alone accounts for the epitome of great precision Cooke dedicated to all of his tasks.
Cooke now tested the invention on the Great Western Railway after engaging in an agreement with Isambard Kingdom Brunel, which he wrote about to Brunel’s sister Mrs. Hawes on 30 May 1838.
This business engagement between Cooke and Brunel successively allowed the use of the Great Western Railway lines for further needed experimental trials with telegraph equipments that Cooke was developing now mainly with Frederick Kerby, his "mechanician." Cooke would later refer to Kerby in this manner during the arbitration proceedings between himself and Wheatstone in the early 1840s. A five needle model of telegraph first constructed during the initial telegraph trials between the London and Birmingham Railway was given up as too expensive. Thus, in 1838, an improvement reduced the number of needles to two, and a patent for this was taken out by Cooke and Wheatstone.
Nearly fourteen months following the May 1838 agreement signed between Cooke and Brunel, and after extensive tests and installations, the telegraph system for the Great Western Railway commenced operations on 9 July 1839. At a cost of £2,817, the line traversed a thirteen mile stretch connecting the Paddington with the West Drayton station. This was part of the London-Paddington to Bristol line of the Great Western Railway and intended for use solely for the internal functions of the railway, and was still experimental. The technology was not to be used for transmittal of messages by the public.