Michael Faraday's major effort in the practical application of science was connected with lighthouses. Between 1836 and 1865 he was scientific adviser to the Corporation of Trinity House the English and Welsh lighthouse authority. In the mid 1850s, he was also appointed lighthouse advisor to the Marine Department of the Board of Trade, who were responsible for the colonial lighthouse service.
In the late 1850s, there was an ultimately unsuccessful move to merge all the British lighthouse authorities (Trinity House, the Northern Lighthouse Board, the Irish Ballast Board and the Board of Trade) into one organisation. This was attempted through the Royal Commission on Lighthouses, for which Faraday played a key role in assessing the technical merits of lighthouse systems, based on detailed work he undertook at Whitby Lighthouse
Faraday had played a key role in the way lighthouses were lit in Britain. In the 1830s, Trinity House lights were relatively backward, especially when compared with those in France. Trinity House lights usually relied on a system consisting of fixed continuous higher and a lower lights so that mariners could check where they were from the relative positions of two fixed points.
Under Faraday's guidance, Trinity House began the introduction of rotating lights using the lenses invented by the French physicist Augustin Fresnel (1788-1827) and introduced into the French lighthouse service by his brother Lénore Fresnel (1790-1869).
In this system, each lighthouse emits a beam of light, or beams, of known duration so that mariners can determine their location. Originally, the large lens systems needed were imported from France. By the 1850s, Chance Bros in Birmingham had started to manufacture glass of sufficient quality that it could be employed, on Faraday's recommendation, in English lighthouses. Trinity House supplied Faraday with resources, in particular the use of Trinity Buoy Wharf
at Blackwall on the Thames, where he could test and observe the performance of lighthouse apparatus using an experimental lighthouse
built specially for him.
In the early 1840s, following a visit to St Catherine's Lighthouse
on the Isle of Wight, he invented a new form of chimney for lighthouses which would prevent the products of combustion settling on the glass of the lanthorn. The result proved so successful that it was installed in all lighthouses run by Trinity House, as well as at the Athenaeum, Buckingham Palace and elsewhere.
Most novel, however, was Faraday's close involvement with various schemes to electrify lighthouses. As early as 1847, it was proposed to electrify lights on buoys. Faraday commented that the buoys had to work perfectly under all weather conditions since an unreliable light was worse than none at all. Despite his evident predilection for electric light, he always gave priority to ensuring the reliability of the light produced by lighthouses.
He didn't develop his own systems of electrical light but was asked to investigate those proposed by others. Some he dismissed quickly but there were two that he spent some time working on, one of which went into operation.
The first, proposed by Joseph John William Watson (c.1831-1886), involved passing an electric current from a battery across a small gap between two rods of carbon. It had been discovered by Humphry Davy in 1810 that this arrangement would produce a very brilliant light in the gap and so it was called a carbon arc. Faraday, after evaluating Watson's scheme for nearly two years from November 1852, rejected it on three grounds. Firstly, the light flickered too much. Secondly, the fumes produced by the nitric acid in the battery were too great. And finally, the operation of the light would require more intelligent lighthouse keepers.
The second system was proposed in the late 1850s by Frederick Hale Holmes (b.c.1811). He too used a carbon arc but its power came from an electro-magnetic machine driven by a steam engine. Furthermore, Holmes had developed a mechanism that would ensure the distance between the carbon poles of the arc remained constant, allowing a sustained and constant quality of light to be produced. After considerable testing by Faraday, Holmes's system was installed in the South Foreland Lighthouse
and first shone on 8th December 1858. Later the system was installed at Dungeness
as well. Though it was not continuously used over the next few years, it was modified to ensure its effectiveness. Faraday undertook much of the monitoring of the light, in which he showed great devotion.
Although electric lights were installed in other lighthouses, the programme was ultimately deemed a failure because of the expense involved and in 1880 it was abandoned. Despite this failure, Faraday had personally overseen one of the earliest practical applications of his invention: the electric generator.