Update: 01-03-2025
Thomas Stevenson was born on July 22, 1818 at 2 Baxters Place in Edinburgh. He was the sixth child of the famous lighthouse engineer Robert Stevenson, and brother of Alan and David Lillie Stevenson.
Thomas was educated, along with other family members of his generation, at the Royal High School and University of Edinburgh and was a pioneering Scottish lighthouse designer and meteorologist, who designed over more than thirty lighthouses in and around Scotland. His designs were ground-breaking, ushered in a new era of lighthouses development.
The profession of Thomas was Civil Engineer and Meteorologist. In partnervessel with his brothers Alan and David Lillie he designed between 1855 and 1886 many lighthouses. When his brother Alan retreated as Engineer of the Northern Lighthouse Board in 1854, he became Chief Engineer (1854-1855) and Senior Engineer (1855 - 1881) and concentrated solely on lighthouse affairs. He designed and built more than twenty-eight beacons and thirty lighthouses. Three of the lighthouses - North Unst (Muckle Flugga), Dhu Heartach (Dubn Artach), and the Chicken Rock - were works of great difficulties.
He began working at his father’s office before his eighteenth year, and after serving a regular pupillage and superintending the execution of various works, he became partner in the firm, with his brothers Alan and David in 1846. The firm was chiefly engaged in the construction of harbour, dock, river, and lighthouse works.
With most rivers and harbours in Scotland, he and his partners were in some way professionally connected, while they were also called upon to design works for the improvement of many rivers and harbours in England and Ireland.
Being the junior member of the firm, he was enabled to devote a large portion of his time to investigations of various kinds. On the subject of harbourconstructions Thomas directed his attention on ascertaining the forces which have to be overcome in the erection of works in heavy seas in deep water.
Thomas put attention on ascertaining the force, height, and laws of propagation of sea waves, and their action on artificial structures. In 1852, after a series of experiments, he drafted the law of the increase of the height of waves. In conjunction to other experiments Thomas put forward in connection to the heights of waves and the various influences the formulas that influence them.
Also to formulas by which the reductive power of harbours and breakwaters could be calculated. All of which are of considerable value to the marine engineering. He always held, however, that much remained to be done, especially in ascertaining facts, and he considered his own work in this direction as only an approximation.
The measurement of the force of waves was carried out with some completeness by means of instruments of his own device. The results of his wave-observations, and the laws deduced from them, were given in papers communicated to the Royal Society of Edinburgh, and to the Edinburgh Philosophical Journal, and in his book on 'Harbours.'
One of his last literary undertakings was the lecture on 'Tides and Coast Works,' read on his behalf, on the 16th of April 1885, because he was unable to be present. He examined wind and wave effects, and his analysis is the first quantitative discussion of wave height. His paper was one of the first quantitative studies of windspeeds in the planetary boundary layer. Motivated by practical applications, these are fundamental contributions.
To lighthouse optics, Thomas devoted special consideration, and devised many notable improvements, both in catoptric and dioptric apparatus and the holophotal system; an optical apparatus for collecting and throwing in a desired direction a large amount of light from a source (such as a lighthouse lamp) by means of lenses or reflectors. In designing these improvements, he was ably assisted by Alan Brebner, M.Inst.C.E. (see also: Technics of the Fresnel lenses)
For a great many of the Scottish Lighthouses, the optical apparatus is of a new design to suit the special requirements of their situations, the latest being the condensing flashing apparatus, for the Isle of Nay Electric Light. In his book on 'Lighthouse construction and illumination,' which has more than three editions, the results of the practice of his firm in lighthouse construction and optics are given. For some of his inventions, submitted to the Royal Scottish Society of Arts, Thomas was awarded with their gold medal.
At the world exhibition of 1878 in Paris, his merits as an inventor in lighthouse optics were likewise recognised with a gold medal. The firm’s advice was taken over by the Governments of India, Newfoundland, New Zealand and Japan. The schemes for lighting the whole coasts of the two last countries were devised by him, and being carried out.
To meteorology, Thomas early devoted his attention. From 1842, when he wrote a paper on 'Defects in Rain Gauges,' he remained interested in meteorology. Thomas has written many papers over the different branches of this subject.
He introduced the use of barometric gradients, as a step towards the numerical measurement of the intensity of storms; and he devised an useful screen for the protection of exposed meteorological instruments, now in very general use, as it rendered observations made at different places comparable with one another.
From the start of the Scottish Meteorological Society, Thomas keenly advocated its interests. He took an active part in all its operations, particularly of the establishment of the Observatory, on Ben Nevis, the highest mountian in Scotland near Fort William
In 1869, as a successful experiment into using the newly invented electric light for lighthouses, Thomas had an underwater cable installed from the eastern part of Granton Harbour, and a light on the end of the Trinity Chain Pier. The light was controlled from half a mile away by an operator on the harbour.
On March 6, 1848 Thomas Stevenson was elected and became Fellow of the Royal Society of Edinburgh, on proposal of: James David Forbes, 28/12/1847, (ms Proposal NLS Acc 10,000/47). (Billet 7/2/1848, 21/2/1848). He acted as Councillor 1868-71, Vice-President 1882-4, President 1884-5.
Thomas came from a family of engineers, all of them highly distinguished in the profession, and of whom five have been members of the Institution. Both in professional and private life he was greatly respected. He was also Fellow of the Society of Antiquaries of Scotland and president of the Royal Scottish Society of Arts (1859–60) and was a co-founder of the Scottish Meteorological Society.He married Margaret Isabella "Maggie" Balfour in 1848, daughter of Rev. Lewis Balfour. Their son was the famous writer Robert Louis Stevenson, who caused him much disappointment by failing to follow the engineering interests of his family.
Thomas was a devoted member of the Church of Scotland. Under the pseudonym of a 'Layman' he wrote several pamphlets on religious questions, one of which was reprinted by the late Professor Crawford for the use of his students. He did much in unostentatious charity, all deserving institutions finding in him a warm and generous supporter.
Thomas was incapacitated for business for some time previous to his death. He spent his last winter at Bournemouth, returning to Edinburgh a fortnight before his death, which took place on the 8th of May, 1887 and is buried in the Stevenson family plot in New Calton Cemetery (also Edinburgh).