Thomas Graham, the first president of the Chemical Society, deserves more recognition for his work than history has given him. Colin Russell attempts to redress the balance.

Thomas Graham, the first president of the Chemical Society, deserves more recognition for his work than history has given him. Colin Russell attempts to redress the balance.

Thomas Graham was a chemist whose work underpins much modern-day chemistry. Yet mention his name and you might notice a blank look on the face of many chemists. Visitors to the RSC’s headquarters at Cambridge, UK - Thomas Graham House - are not infrequently heard to enquire who this Thomas Graham was, and why he should have given his name to the RSC’s building.  

Their ignorance is pardonable for, although Graham was a great chemist, he is rarely heard of these days. Those with long memories may possibly recall something about Graham’s law of gaseous diffusion from their school or undergraduate days, but probably not much more.  

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Thomas Graham, the first president of the Chemical Society

Yet Graham is worth paying tribute to because he was the first president of the world’s first national society for chemists, the Chemical Society of London - precursor to the RSC. This epochal event happened in 1841, after London chemist Robert Warington had convened a meeting in the rooms of the Royal Society of Arts, ’for the purpose of taking into consideration the formation of a Chemical Society’.  

The name was agreed as the Chemical Society of London; a library and museum were established, and meetings were to be reported in Proceedings  or Transactions. This later became its most important function. At its first formal meeting a month later, the founding members numbered 77; in 1848, when the charter of incorporation was granted, there were over 300 fellows. 

Prestigious position 

For Victorian societies, appointing a president was a matter of prestige. In 1841 the privilege fell to a sandy-haired young Scotsman, rather diffident, fairly new to the London scene, but with a rising reputation. His name was Thomas Graham.  

The favourite had been Sir John Herschel, the astronomer, but he declined on the entirely proper grounds of an ’imperfect acquaintance with chemistry’, even though he had done significant chemical work in the infant science of photography. Two others who refused were Michael Faraday and Richard Phillips.  

Graham was thus fourth choice, and in achieving even that position he seems to have owed much to the support of chemists from overseas, notably Justus von Liebig. Indeed the first paper at the first scientific meeting (April 1841) was a communication by Liebig on Yellow prussiate of potash, read for him by Graham.  

Warington’s original idea had been to provide a general service to chemists by bonding the chemical community together, so dispelling factional interests and the hostility between ’science and practice’. Within a few days, however, this vision was to be subtly changed: what chemistry most needed was a scholarly forum, more specific and less intimidating than the grand meetings of the Royal Society.  

That was the view of the first president, and his vision shaped the destiny of the new society. Graham was elected a second time in 1845, a sure sign that by then he was accepted in the inner circle of leading chemists. 

Following a calling to chemistry 

This year is Graham’s bicentenary. He was born in Glasgow on 21 December 1805, to a prosperous merchant and fabric manufacturer. His father intended him for the Church of Scotland ministry and Thomas duly entered Glasgow University to study the arts. However, by the end of his five-year stay he had taken a chemical lecture course given by Thomas Thomson. From now on he was completely won over to chemistry.  

In a further two years, when he was supposed to be studying theology, he immersed himself in the physical sciences and even began research on gaseous absorption. His father seems to have been unusually gullible, for he then consented to his son’s transfer to the University of Edinburgh, for the odd reason that divinity lectures there were alleged to be better. This was all the more remarkable since he enrolled as a medical student. In those days medicine offered the only way to chemical qualification. From 1822 to 1824 his mentor was T C Hope, successor to Joseph Black as professor of chemistry and an excellent teacher of the subject.  

Graham’s mother and sister connived in this strategy of deception. At length his father saw the light, when he visited his rooms and discovered them full of chemical apparatus rather than theological tomes. He furiously cut off his son’s support. So Thomas had to return to Glasgow. It was a great gain for chemistry, but also for the Church, which was spared from having a minister with no sense of vocation. 

Beginnings of gaseous diffusion 

Back in his native city, Graham supported himself with a variety of teaching activities, including chemical lectures at the Glasgow Mechanics’ Institution. He also submitted to the university’s medical faculty an essay on gaseous diffusion. Diffusion of gases had been observed earlier (by D?bereiner) but this was the first systematic approach to the subject.  

On the strength of this essay he was granted membership and almost immediately afterwards was appointed professor of chemistry at Anderson’s Institution (1830). This promotion was sufficient for his father to relent and for reconciliation between them. At the Andersonian Graham lectured (though with no great eloquence) and, almost for the first time in the UK, offered courses of laboratory instruction. He also found time to continue research on gaseous diffusion and within a year announced to the Royal Society of Edinburgh what we now call ’Graham’s Law’; that the rate of diffusion of a gas is inversely proportional to the square root of its density. 

Following Thomson’s lead, Graham became an enthusiastic supporter of the atomic theory first suggested by John Dalton in the early 1800s. Now, 20-something years on, the original Daltonian symbols were becoming increasingly cumbersome. So Graham turned to those recently invented by Berzelius, where the old circular symbols were replaced by one or two letters for each atom, as we still write today. He was an early recruit to the British Association, and found that its section B was a good place to promote this new Berzelian expression of atomism.  

"Graham became an enthusiastic supporter of the atomic theory first suggested by John Dalton"

His new formulae enabled him to represent more clearly a new view of the arsenic and phosphoric acids that he now turned to examine. Again borrowing from Berzelius, he viewed these and other acids as compounds of water and a non-metallic oxide. He solved the problem of three kinds of phosphoric acid by recognising the different amounts of combining water.  

His symbols were still marred by the wrong (Daltonian) formula for water as HO, but translating them into modern terms they become 3H2O.P2O5, 2H2O.P2O5 and H2O.P2O5 for ortho-, pyro- and meta-phosphoric acids respectively. This was a path-breaking paper in inorganic chemistry, and was read to the Royal Society in 1833.  

Opposing opinions 

This research was not appreciated by all. Graham’s opponents included those like William Whewell who disliked such new-fangled formulae, and (by a strange irony) Berzelius himself, who thought the differences were due to isomerism.  

But Graham’s commitment to atomism remained throughout his life. Other early work included studies of the glow of phosphorus and the inflammability of phosphine. One of his students was James (’paraffin’) Young, who assisted Graham for some years, founded the Scottish shale-oil industry in 1850 and financed the African journeys of David Livingstone. 

By now Graham was generally recognised as a world-class chemist. He became a FRS in 1836 and won the Royal Society’s Royal medal two years later. In 1837 he got his big break: a chair of chemistry at University College London (UCL). This had the great advantage of bringing him into contact with far more chemists than he was likely to meet in Glasgow and in a few years facilitated his presidency of the infant Chemical Society.  

He also remained heavily involved with promoting chemistry within the British Association as well as with the chemical committee of the Royal Society. He urged that the new Chemical Society should open its doors to foreign chemists and welcome their contributions to its journal.  

One overseas chemist who admired Graham’s work was that pioneer of agricultural chemistry and founder of the great research school in Giessen - Liebig. The two had met in 1836, and in the following year Liebig was guest of honour at Graham’s farewell dinner in Scotland before his departure for UCL. Admiration was mutual; Graham addressing Liebig as ’my dearest friend’. Years later, in 1845, Graham confessed to ’dissipating my evenings lately with Bunsen and Liebig’, who were visiting for a week. 

Lecture classes and lab courses 

Life in London was not all jolly social events with other chemists. At UCL, Graham had large lecture classes, many of them for medical students. He did not enjoy this activity but needed the income it provided, over ?700 one year. Laboratory courses attracted fewer numbers, which was just as well since they paid less.  

Almost immediately he began publication of his Elements of chemistry, though the final part did not appear until 1841. This not only advocated the atomic theory but also included the latest discoveries in physics and physiology, where these related to chemistry. This was a different emphasis from most of the chemists in London who, following Humphry Davy, tended to major on the chemical implications of electricity instead. 

At UCL, Graham took ’stolen snatches’ for research, continuing to work on diffusion of gases. He distinguished between diffusion (through a porous wall) and transpiration (through a capillary tube). Their rate laws were found to be quite distinct. From 1848 he extended this work to liquids, showing that the rate of diffusion of a solute was roughly proportional to its concentration.  

His Bakerian lecture to the Royal Society in 1848 was about The diffusion of liquids and described many experiments in which salt diffused from a concentrated solution into a layer of pure water carefully introduced above it.  

At about the same time, he confronted the bewildering variety of effects associated with osmosis, a phenomenon discovered by the French Abb? Nollet a century before. Graham concluded that two processes were occurring, diffusion of a solute through a membrane, and diffusion of the solvent (usually water) in the opposite direction.  

"Graham confronted the bewildering variety of effects associated with osmosis"

He coined the terms osmotic force, to explain these effects, and osmometer, as an instrument to measure them. He came back to this theme many years later.  

Other research included a study of the metal ammines, and he became the first to regard these as substituted ammonium compounds like NH3-CuCl2-NH3. Graham also devised the sand tray for heating flasks. 

As if teaching, writing, research and chemical conviviality were not enough, this indefatigable chemist undertook much consultancy work for the government and others. His research included the ventilation of parliament, the supply of drinking water to London and the ’original gravity’ of beer.  

For some time he also helped the scientific assay of gold and silver on behalf of the Royal Mint. Sir John Herschel had been master of the mint since 1850, and when he retired five years later Graham was well placed to succeed him, and therefore resigned his chair at UCL. After his death, the mastership lapsed; its functions were taken up by the chancellor of the exchequer. 

Demands on a chemist’s time 

Graham’s first years as master were demanding and saw bronze replace copper as a coinage metal. Little time was available for private research, as he frequently complained in his correspondence. However, from about 1860 he was able return to studies of liquid diffusion. He noted a range of different properties among apparently dissolved materials, from simple salts to jellies and glues. He invented for them the names crystalloid and colloid (from the Greek word for glue) and so became the founder of colloid chemistry.  

The semi-permeable membrane that he advocated was ’a sheet of very thin and well-sized letter paper, of French manufacture’, so permitting the process of dialysis (another Graham term). His dialyser enabled him to determine the rates of diffusion and also to separate and collect purified crystalloids and colloids. Graham thought that the ’peculiar physical aggregation’ of colloids might be significant to the processes of life. Clearly the dialyser was a powerful tool for analysis and purification, but it was not generally appreciated until after Graham’s death, when it became largely applied to inorganic colloids such as gold and silica. 

Gas separation 

These studies of diffusion were closely related to Graham’s atomic speculations. Inspired by the recently revived kinetic theory of gases, he wrote a paper in 1863, On the molecular mobility of gases, describing the effects of graphite membranes. He showed how gases like hydrogen and oxygen might be separated in this way, a process used in the second world war on UF6 to separate uranium isotopes.  

In an appendix entitled Speculative ideas respecting the constitution of matter, Graham suggested that differences in atomic motion could be due to differences in what we should call sub-atomic particles. He discovered what he called the ’occlusion’ of hydrogen by palladium and wondered if hydrogen might not be some kind of metal. 

Graham’s preoccupation with atomism is a key to his whole philosophy. At a time when atoms were regarded by some chemists as imaginary objects, he devoted his life to tracking their movements, as they passed through solid walls, encountered animal and vegetable materials and mixed with each other in space or solution. By so doing, he discovered a fundamental law of diffusion, laid the foundations for the science of colloids, and kept alive the indispensable idea of atoms.  

Graham maintained strong links with his family but he never married. His life at the Royal Mint continued at the relentless pace he imposed on himself. Inevitably his health deteriorated, and after an attempted convalescence at Malvern he died in his London home on 16 September 1869. The world had lost the first president of the Chemical Society, the last successor of Sir Isaac Newton as master of the mint, and one of the founders of physical chemistry. 

Colin Russell is emeritus professor in the department of history of science at the Open University and affiliated research scholar at the department of history and philosophy, University of Cambridge, UK 

Further Reading

  • R A Smith, The life and works of Thomas Graham,Glasgow, 1884. 
  • M Stanley, New dictionary of national biography
  • M M Pattison Muir, Heroes of science: chemists, London, 1883, pp. 232-251. 
  • J R Partington, A history of chemistry, vol. iv, London, 1964, pp. 265-276. 
  • A W Williamson, J. Chem. Soc., 1870,  23 , 293