44. Clapham Scientists – adding to the tally
31st January 2025
By Timothy M M Baker.
Clapham’s status as a fashionable suburb in the great era of amateur science in the eighteenth and early nineteenth centuries, perhaps combined with its reformist and radical reputation, attracted a number of distinguished scientists who have been the subject of several articles in the Clapham Society’s Local History Series.
This new article signposts those and adds four more to the tally.
7. Michael Green’s Mount Pond, Clapham Common: Archaeology and History, 2010, on the Pennsylvanian philomath Benjamin Franklin’s experiment on the Pond, while visiting Christopher Baldwin in the 1760s, to demonstrate the effect of ‘pouring oil on troubled waters’.
8. John Toman’s Francis Kilvert and Charles Pritchard: Clapham Connections, 2011, on the mid-19th-century scientific coterie that spawned the Clapham Athenaeum; astronomer Charles Pritchard, who was headmaster of Clapham Grammar School and later Savilian Professor of Astronomy at Oxford; palaeontologist Gideon Mantell, the discoverer of Wealden dinosaurs; and the geologist Joseph Prestwich, who was born in Clapham, though his work was focused in South Lambeth and later at Oxford.
29. Peter Jefferson-Smith’s Two American Visitors to Clapham, 2018, on Benjamin Franklin’s visit.
31. Derrick Johnson’s Eccentric Scientist Who Weighed the Earth, 2018, on Henry Cavendish’s ‘Cavendish Experiment’ of 1797-1798 – completing work that had been started by his friend the Yorkshire clergyman, astronomer, and Newtonian physicist John Michell – to measure the density of the Earth.
42. This author’s John Peter Gassiot, James Clerk Maxwell, and the Speed of Light, 2024, on Clapham electrical experimenter JP Gassiot, and the great Scottish physicist James Clerk Maxwell’s use of his powerful batteries at Clapham to measure the ratio of electrical forces, and its correspondence to the speed of light.
43. This author’s Henry Cavendish’s Astronomical Observatory, 2025, providing more detail on Cavendish’s transit room at Cavendish House, and its role in William Roy’s geodetic triangulation of the London area.
These accounts do not exhaust the tally of eminent Clapham scientists. This article describes the continuation of the earlier tradition of suburban science into the nineteenth century. By then, however, the scientific scene in Clapham was beginning to be inhabited by professional scientists and engineers, some of whom worked in Town. The chemist Friedrich Kekulé had one of his greatest theoretical insights while commuting home on the Clapham Omnibus. Marine engineer Frank Wenham lived in Brixton but had a workshop in Clapham where he undertook pioneering experiments in heavier-than-air flight. James Wimshurst, another professional marine engineer but like Gassiot an amateur electrician, invented at Clapham the eponymous ‘Wimshurst Machine’ electrostatic generator. Much later, in the mid-twentieth century, the audio and video engineer Ray Dolby set up his laboratories in the Clapham Road.
Friedrich August Kekulé (1829-1896). A German chemist, he lived at 3 Dudley Villas (later 249 Clapham Road, its site on the east side mid-way between Stockwell Road and Lingham Road) during the time that he worked at St Bartholomew’s Hospital in the City of London, 1853-1855. Kekulé was heavily influenced by Alexander Williamson, of University College, London, and Edward Frankland, of Owens College, Manchester, towards the unorthodox structural theory of chemistry. The prevailing view in the early 1850s was that the details of chemical structures, in particular of organic molecules, were unknowable. Williamson’s and Frankland’s ‘theory of types’, instead focused on classification of elements according to their chemical behaviour and ‘atomicity’ (valency).
Inspired by Williamson, in 1854 Kekulé was on his way home along the Kennington Road aboard the Clapham omnibus, when he had a ‘waking dream’, in which he saw atoms grouping themselves into definite structures to form molecules. The essential features of his theory were the ability of other elements (such as sulphur) to replace oxygen in ‘water types’ – with each of these ‘diatomic’ elements always bonding to two other atoms or radicals (H₂O, H₂S).
Kekulé went on to identify ‘monoatomic’ and ‘triatomic’ elements, and, fully developing Frankland’s valency theory, the ‘tetraatomicity’, or 4-valency, of carbon atoms, which enables them to link with each other into chains, while radicals attach via the two remaining bonds. Kekulé maintained that it was possible to ascertain molecular structures by analysing the products of reactions into their constituent atoms. The Scottish chemist Archibald Couper developed similar ideas in parallel, but Kekulé published first, in 1858. Kekulé’s theory enabled chemists to model a wide range of organic molecules, facilitating both their analysis and synthesis, prompting a huge growth in organic chemistry, and opening the path to stereochemistry. One of the most important of Kekulé’s later discoveries, in 1865, by when he was working at Ghent University, was the hexagonal ring structure of the benzene molecule (C₆H₆).
(Later in the 19th century the judge Lord Bowen coined the term ‘the man on the Clapham Omnibus’ to describe the ordinary reasonable man. From its first published use, by Lord Collins in 1903 in the case of Lord McQuire v Western Morning News, the term came to become the legal designation of such a person. An original horse-drawn Clapham Omnibus, of that type that Kekulé rode, is preserved in the London Bus Museum at Brooklands.)
Francis Herbert Wenham (1824-1908). A marine engineer, he lived in the 1850s and 1860s at Effra Vale Lodge, Effra Road, Brixton, from where he took out a number of patents for various devices, and which was also listed as his address in the early reports of the Aeronautical Society of Great Britain. However, he took out his famous 7th June 1866 patent No 1571, with a provisional specification for ‘Improvements in Apparatus for Aerial Navigation’, from Union Road, Clapham. Wenham’s 1864 Patent for improvements to gas engines (No 1174) also came from Union Road. So it appears that, while he lived at Brixton, he had a workshop at Union Road.
One of the founders in 1866 of the Royal Aeronautical Society of Great Britain (later the Royal Aeronautical Society), Wenham published a paper at the Society’s first meeting, based on his experiments from the late 1850s, on the aerodynamics of wings. He concluded that most lift was given by a wing’s leading edge, and that wings should therefore be long and narrow (a relationship later known as the ‘aspect ratio’) to maximise lift and minimise weight: a result confirmed by the 20th century mathematical theory of flight efficiency. Wenham identified the potential for superposed wings in a biplane or multiplane to increase lift, and himself experimented in flying a ‘Venetian blind’ multiplane glider, with up to five wings, stacked one above the other; as he recalled in his 1866 paper:
‘This was taken out after dark into a wet piece of meadow land, one November evening, during a strong breeze, wherein it became quite unmanageable. The wind acting upon the already tightly stretched webs, their united pull caused the central boards to bend considerably, with a twisting, vibratory motion. During a lull, the head and shoulders were inserted in the triangle, with the chest resting on the base board. A sudden gust caught up the experimenter, who was carried some distance from the ground, and the affair falling over sideways, broke up the right-hand set of webs.’
The 1874 25-inch Ordnance Survey map shows a few fields still clinging on, both to the south of Union Road, Clapham, and on the flanks of Effra Road, Brixton, so we cannot be certain where Wenham’s damp meadow was. The Union Road fields surrounded George Man Burrows’s lunatic asylum ‘The Retreat’: which might seem a suitable location, perhaps, for a Victorian experiment in flying.
Wenham’s biplane design, with the wings linked by struts and the pilot lying horizontally, was the basis of the Wright brothers’ ‘Flyer I’ and other early aeroplanes. In 1871, with City of London instrument maker John Browning, Wenham built the first, steam-driven, wind-tunnel, at John Penn & Son’s marine engineering works at Blackheath Hill, Greenwich.
James Wimshurst (1832-1903). Another marine engineer, from 1874 he worked as a shipwright surveyor for the Board of Trade. His house was at 7 Crescent Grove, Clapham where he built extensive workshops and, like JP Gassiot an amateur electrician, he had an electrical laboratory.
He experimented with ‘electrical influence machines’, which by the turning of a winch could accumulate enough static electricity to produce long sparks for experimentation and entertainment. The different types of machine were named after their inventors. In the 1880s Wimshurst duly invented the Wimshurst machine, in which two insulated plates rotated against each other, their friction generating charge that accumulated on conducting metal ‘sectors’ attached to their outer faces. He did not patent the design, and both Wimshurst and commercial instrument makers built Wimshurst machines.
In 1896 Wimshurst found that his machines could excite X-rays. They were widely used in early experiments on vacuum discharge and X-rays, and as X-ray generators for radiotherapy.
Wimshurst combined his marine and electrical expertise by inventing improved methods for connecting lightships with their shore stations.
Ray Dolby (1933-2013). An American audio and video tape engineer, who had done graduate research at Cambridge, in 1965 he established Dolby Laboratories at 346 Clapham Road, on the north corner with Union Road, where he remained until 1976.
In 1965 he invented the Dolby noise reduction system, which reduced the audible hiss on analogue sound recordings by increasing the volume of high-frequency sounds during recording, then reducing their volume during playback. The system was first used for audio tape by Decca. Dolby went on to develop noise-reduction systems for optical sound on video-tape, deployed in cinema from 1971.