[4] South Foreland Lower Lighthouse was built at the same time further down the cliff, to the east, where it still stands; decommissioned in 1904, it is now in private ownership.
In the 1850s Michael Faraday, scientific adviser to Trinity House, was exploring the feasibility of electric light being used in lighthouses; several different solutions were proposed.
[9] The South Foreland trial began in December 1858 and continued until early 1860; afterwards Holmes's equipment was installed on a more permanent basis in Dungeness Lighthouse, in 1862.
[11] A power station was built mid-way between the two lighthouses containing four Holmes magneto-electric generators (two for each light), driven by a pair of 10hp Hunter & English horizontal steam engines fed by coke-fuelled Cornish boilers.
[14] In 1873 Professor Tyndall was engaged by Trinity House to conduct a series of experiments on the relative effectiveness of different types of fog signal.
[15] South Foreland, with its recently installed steam power plant, was chosen as the location and a variety of acoustic instruments were set up at the top and bottom of the cliff, to be monitored from a Trinity House vessel offshore.
Later, other designs of whistle were trialled, as well as a steam 'syren' (provided by Joseph Henry) and three types of gun (operated by gunners from Dover Castle).
[15] Tyndall presented wider conclusions on the acoustic effects of different atmospheric conditions in a paper delivered to the Royal Society the following year.
[16] In 1876 Tyndall was again engaged to make a comparative study at South Foreland, this time of two different types of electric generator: the magneto and the dynamo.
[17] (In 1869 Holmes had speculatively constructed a pair of dynamos and suggested them for the permanent South Foreland installation, but at the time they were not considered sufficiently tried and tested.)
[20] In 1898 South Foreland Lighthouse was used by Guglielmo Marconi during his work on radio waves, receiving the first ship-to-shore message from the East Goodwin lightship on Christmas Eve that year.
[25] In 1925 Guglielmo Marconi returned to South Foreland and installed an experimental radio guidance system: a slowly revolving frame antenna (described at the time as a 'wireless lighthouse') which emitted different signals for different compass bearings; it was designed to enable vessels to fix their position even in poor visibility.
There is no vehicle access to the site; visitors are advised to walk either from Dover or from St Margaret's village, or else to use the nearby cycle route.