Semaphore signals were developed in France at the end of the 18th century, before being later adopted by the railways. The first railway semaphore was erected by Charles Hutton Gregory on the London and Croydon Railway (later the Brighton) at New Cross Gate, southeast London, in 1841. It was similar in form to the optical telegraphs then being replaced on land by the electric telegraph. Gregory's installation was inspected and approved for the Board of Trade by Major-General Charles Pasley. Pasley had invented a system of optical telegraphy through semaphores in 1822 for the British military, and appears to have suggested to Gregory the application of the semaphore to railway signaling. The semaphore was afterwards rapidly adopted as a fixed signal nearly universally. Disc signals, such as those made by the Hall Signal Company, were sometimes used, but semaphores could be read at much longer distances. The invention of the electric light, which could be made brighter than oil lamps and hence visible both by night and day, resulted in the development of position light signals and colour-light signals at the beginning of the 20th century, which gradually displaced semaphores. A few remain in modern operations in the United Kingdom.