There is no doubt but that track circuits were thought of and actually experimented with in England a great many years ago--probably as far back as the earliest American attempts--but the want of satisfactory records make it very difficult to decide on what actually took place. However, it is certain that the late W. R. Sykes, well-known throughout the railway world for his controlled manual block and other inventions, endeavored to use the track circuit in the sixties and that Bull, the inventor of the bull-headed rail employed in England for the chaired track universally found there, clearly had the idea of a track circuit in his mind, for he refers to it in a patent obtained in 1860. It was apparently in the early part of the sixties that W. R. Sykes fixed a track circuit experimentally at Briseton on the old London, Chatham and Dover Railway, and shortly after also at the Crystal Palace Station on the same line. The apparatus employed must necessarily have been rather primitive. In the seventies, track circuit was installed by him at St. Paul's station, also on the Chatham Railway. At that time very little was known about the track circuit theoretically and the construction of the relay was very different from our modern types. Sykes' relay completed the control circuit by the insertion of a contact point into a mercury trough. It was also, the writer believes, built on the solenoid principle. So far as is known it was not suggested at this time and at all events not attempted to make an automatic block system controlled by track circuits, such schemes for signaling of this type as were put forward being always based on the intermittent or track instrument control plan.