Balfour Stewart

M.A., LL.D., F.R.S.

Balfour Stewart
  • Born:

    Edinburgh, 1 November 1828

  • Died:

    Ballymagarvey, 19 December 1887

  • Father:

    William Stewart of Burness

  • Mother:

    Jane Clouston

  • Married:

    Katherine Stevens

  • Children:

    Charles, William, Jane

The Royal Society of London was founded almost exactly 350 years ago, in November 1660, "to assist and promote the accumulation of useful knowledge". It is still active today and Bill Bryson, in the book he recently edited about the Society, Seeing Further, The Story of Science & The Royal Society, describes it as not only the most venerable learned society in the world but the finest club.

Balfour Stewart was born in Edinburgh but his pedigree is impeccably Orcadian. His father was a younger son of the Stewarts of Brugh in Westray and his mother was a daughter of William Clouston, minister of Stromness and Sandwick and author of the fascinatingly detailed record of his parishes in the Statistical Account of Scotland

William Stewart was a tea merchant in Leith but Balfour is recorded as going to school in Dundee and briefly attending St Andrews University before matriculating at Edinburgh University in 1844 when still not quite sixteen. He spent two years there but, for reasons that are unclear, he left without completing his degree and was apprenticed to his cousin James Balfour, a merchant in Leith. After seven years there he went to Australia with James but returned as a scientist just eighteen months later.

While in Australia he had presented two papers to the Philosophical Society of Victoria, on the effect of gravity on the physical appearance of the moon and on the adaptation of the eyes to the rays which emanate from bodies. According to the Dictionary of National Biography these papers were published in 1855 but, according to the Edinburgh University records, he returned to his studies that same year. His student career is altogether puzzling as, on the recommendation of his professor, James David Forbes, he was taken on as an assistant observer at the Kew Observatory in February 1856 but went back to university in October and graduated in April 1857.

After graduation, Stewart became an assistant to JD Forbes, lecturing on mathematics and mechanics and joining him in his study of heat. He made the important discovery that radiation isn't just a surface phenomenon but passes through the interior of the radiating body. He also established that an object must absorb and radiate energy of the same length. This was important in the development of spectrum analysis. However, after just two years Balfour Stewart was back at Kew, this time as its Director.

Kew Observatory had been built to allow George III to observe the transit of Venus in 1769 and was then leased to the British Association for the Advancement of Science, to be used in the study of the physical sciences. The Association had been founded in 1831, to combat what its founders saw as the decline of science due to the elitism of the Royal Society and the unprofessional status of scientific practitioners. The Society held its AGM in a different town or city every year and formed various committees to report on recent developments in different scientific fields. The Kew Committee was one of these.

When Stewart left after his first brief employment, the Committee minuted their regret at his departure and added,

"The Committee refer with pleasure to an ingenious thermometer devised by Mr. Stewart, in which advantage has been taken of the difference of capillary force and friction in two tubes of different capacity connected with the same bulb, to measure the sum of the fluctuations of temperature. The instrument has been made at the expense of the Committee; a description of it has been communicated by Mr. Stewart to the Royal Society and is printed in its "Proceedings."

He clearly made quite an impression, to be offered the post of Director while still only thirty. He had maintained a connection with Kew, according to Katherine Anderson in Predicting the Weather: Victorians and the Science of Meteorology, working on a survey of terrestrial magnetism with the director, John Welsh, whose death led to Balfour Stewart's appointment.

The unique self-recording magnetographs at Kew measured the declination and horizontal and vertical intensity of the earth's magnetic elements. The Observatory staff had to make their own photographic paper, replace it every 24 hours, develop the photographs, and make copies if necessary.

The Kew Observatory also had a heliograph, with which they made a detailed study of the sun. Stewart's arrival at Kew was greeted by the most powerful solar storm ever recorded. The astronomer Richard Carrington is credited with the first recording of a super flare, on 1 September 1859, but Stewart had recorded one four days earlier, which he described in a paper presented to the Royal Society on 21 November 1861 ( It took only eighteen hours to reach the Earth and seriously affected the telegraph system. Stewart's study of the 1859 storm led him to suggest a connection between solar behaviour and terrestrial phenomena.

Stewart published the first paper to suggest the presence of an electrified atmospheric layer. This was later named the ionosphere by Robert Watson Watt, the 'father of radar' who had been taught physics at Dundee University by Professor William Peddie, son of the Free Church minister in Papa Westray. Edinburgh University's Meteorology Department recognised his work on the earth's magnetic field in the name of its Balfour Stewart Auroral Laboratory which studied aurora and noctilucent cloud 1947 to1980.

In the second half of the 19th Century, the need for accurate scientific instruments increased rapidly. More and more scientists and explorers needed reliable instruments if there work was to have any value. Stewart led Kew to become the national centre for the standardisation of thermometers, sextants and other meteorological instruments. During his time at Kew the number of instruments being verified increased sharply, over 1000 thermometers in some years. They standardised and tested thermometers, sextants, dipping needles, and other instruments for meteorological or magnetic work. Instruments were sent overseas: a dip circle and azimuth compass to Dr Livingstone and instruments to Alexander Strange, grandson of Sir Robert Strange from Kirkwall, who was working on the great triangulation of India.

In 1862 Stewart was made a member of the Royal Society. When a name is put forward, members of the Society can support the proposal, either from general knowledge of the proposed member or from personal knowledge. Those with general knowledge included the astronomer JFW Herschel and Andrew Scott Waugh, the Surveyor General of India, but there is a longer list of members with personal knowledge. These include JD Forbes, Richard Carrington, Charles Wheatstone, inventor of the Wheatstone bridge, and Admiral Robert Fitzroy, ex-captain of the Beagle but one name stands out from all the rest, Michael Faraday.

In 1868 Stewart was awarded the Royal Society's Rumford Medal for his discoveries in the radiation of heat, having published a widely- read treatise (google book) on the subject two years earlier. The Rumford Medal is awarded for outstandingly important discoveries in the field of thermal or optical properties. It was established by Benjamin Thompson, known as Count Rumford, who founded the Royal Institution and appointed architect and geologist Thomas Webster from Papa Westray as the clerk of works. Balfour Stewart is in good company: other recipients of the medal include Humphrey Davy, Michael Faraday, James Clerk Maxwell, Ernest Rutherford and Frank Whittle.

In January 1867 Balfour was appointed secretary to the newly formed government Meteorological Committee. It had been set up to oversee the operation of the Meteorological Department (later the Met Office). One of the first actions of the Committee was to set up a network of autographic (producing continuous traces of the meteorological elements) weather stations around the UK. They were to be at Kew, Falmouth, Stonyhurst, Armagh, Glasgow and Aberdeen. Valentia in south-west Ireland was added in 1868.

Kew Observatory was to be the lead station, and the autographic instruments were to be built there by the mechanic, Richard Beckley, under Stewart's direction. Stewart visited several of the sites and by August 1867 he was able to report to the Committee that the anemographs, recording wind speed, were ready and the other instruments would be ready in a few days. All the observatories were ready by August 1868. Stewart provided lengthy and detailed reports on the state and performance of the instruments to the Met Committee. In the next two years he supervised the installation of meteorological stations all over the country but resigned from the committee in 1869 and left Kew the following year, to move on to the last phase of his remarkable career.

Owens College was founded in Manchester in 1851, the year of the Great Exhibition. Textile merchant John Owens had left enough money to found a college for young men but it wasn't a success at first because the self-made industrialists of the town didn't see any advantage in sending their sons to college. Then, as the Victorian Age gathered steam, the importance of science to the development of industry became apparent. In 'Cottonopolis' the usefulness of chemistry in the production of dyes was already recognised and Henry Roscoe, (grandson of William Roscoe, friend of Professor Thomas Stewart Traill and subject of essay by Washington Irving) professor of Chemistry at the college, insisted that it was impossible to be a useful chemist without understanding the basic principles.

Owens College developed the best school of chemistry in the country but by 1870 the college wanted to improve its provision in other sciences. Roscoe invited Balfour Stewart, who had already published papers on astronomy, meteorology, chemistry, mathematics and physics, to apply for the soon-to-be-vacant position at the head of the physics department.

Roscoe had suggested there should be chairs in experimental physics and applied mathematics but Stewart wrote to him in June 1870,

"I do not think the division of the subject into applied mathematics and Experimental Physics a good one for Natural Philosophy without experiment is merely a mathematical exercise while experiment without mathematics will neither sufficiently discipline the mind nor sufficiently extend our knowledge in a subject like Physics."

He described how the proposed new physical laboratory would be used.

" The Physical Laboratory would not only be used in experimental illustrations of certain laws enunciated in the lectures but I think that some observational and also some experimental research ought always to be going on in order that the more advanced students should be brought into contact with nature. Then they ought to be taught the use of the various instruments and set to devise and work out experiments. They ought also to be taught the philosophy of experiment.

1. To pay attention to and evaluate all sources of error giving due weight to each and dismissing those that ought to be disregarded (thus it is a very common mistake to give inordinate importance to some utterly useless refinement)

2. To pay strict attention to [natural] phenomena as … something new

3. To reach the legitimate conclusion from an experiment no more and no less."

Unfortunately, in November 1870 Balfour Stewart was involved in a serious train crash. His thigh was crushed in an accident at Harrow and he was bed-ridden for nine months. He was never the same man again; although only forty-two he described himself as having passed from vigorous activity to grey-headed old age. However, he was far from done yet, some of his most important contributions to physics were still to come.

Under Balfour Stewart the physics department became one of the first in the country to teach its students how to conduct experiments and it developed into the world-class facility it was to remain. Stewart's successors in Manchester include Ernest Rutherford and Brian Cox.

The universities of the time were slow to recognise the importance of the teaching of experimental science. Bertrand Russell, in The Scientific Outlook in 1931 claimed that when it was proposed to establish laboratories at Cambridge the mathematician Isaac Todhunter objected that it was unnecessary for students to see experiments performed, since the results could be vouched for by their teachers, all of them of the highest character, and many of them clergymen of the Church of England. In the long run, Stewart's teaching methods were vindicated in the most spectacular way possible: two of his students won the Nobel prize for physics.

Sir Joseph John Thomson, known as JJ Thomson was awarded his prize in 1906, for the discovery of the electron and investigations on the conduction of electricity by gases.

James Navarro in A History of the Electron: J.J. and G.P. Thomson, 2012 is the latest writer to note the profound effect Balfour Stewart had on JJ Thomson's career.

"But as some historians have emphasised, it was Balfour Stewart who probably most influenced Thomson at Owens College. On the one hand, he introduced J.J. to Maxwell's recent Treatise on Electricity and Magnetism, arousing his interest in this science. On the other hand, Stewart was passionate about teaching in the laboratory, and he brought Thomson into hands-on practical research. They spent long hours together, engaged in laboratory work, trying for instance, to detect a change of weight in chemical reactions. Although Stewart was formally a professor of physics, his research topics were at the boundary between physics and chemistry, which contributed to Thomson's idea that both disciplines were part of a bigger whole. For example, Stewart organised practical courses for three kinds of students, including those "who wish to confine themselves to those branches of Physics most allied to Chemistry". In his study of Thomson's inclination towards chemistry , Sinclair emphasised that Stewart's ideas on the conservation of energy, the constitution of matter, the nature of the aether and of the atoms, etc, were extremely influential on J.J., which explains that he always saw many physical problems "in something of a chemical light"."

JJ Thomson came to Owens College in 1870, the same year as Balfour Stewart, when he was just fourteen. Six years later he went to Cambridge and stayed there, becoming Cavendish Professor of Physics. He was in his turn a gifted teacher, seven of his research students and his son won Nobel Prizes, so it could be said that Stewart's influence spread far and wide.

Charles Thomson Rees Wilson was awarded his Nobel Prize in 1927, for the invention of the cloud chamber, which can detect particles. He went to Owens College in 1884 aiming to become a doctor and Stewart is credited with playing a large part in leading him into physics and meteorology instead. Time he later spent working at the Ben Nevis Observatory with RT Omand, son of Robert Omand, surgeon from Kirkwall, and grandson of Thomas Stewart Traill helped to provide the inspiration for his invention.

Owens College students sat the examinations set by University College, London but these became less and less suitable. In July 1877 a delegation from the College, including Balfour Stewart and Henry Roscoe, presented a memorial to the president of the Privy Council proposing that they should become a university. Other northern colleges objected strenuously and a compromise was reached: a federal university. Liverpool and Leeds joined Manchester in the Victoria University but by 1903 they had gone their separate ways and the University of Manchester was established.

Balfour Stewart was an active member of the British Association of the Advancement of Science and in 1875 he was President of the Mathematical and Physical Science Section. Although he had left the Kew Observatory seven years earlier, his presidential address, which can be read online, was largely concerned with solar research and the sun's effect on the earth. He remarked on how two branches of science, physics and chemistry, meet in solar research and went on, "Why should we not erect a sort of science exchange into which the physicist, the chemist, and the geologist may each carry the fruits of his research, receiving back in return some suggestion, some principle, or some other scientific commodity that will aid him in his own field."

Remarkably he went on to mention another scientist with strong Orcadian connections. Alexander Strange had become a member of the Royal Society and the BAAS when he came back from triangulating India and, as Stewart reminded his audience, at the Norwich meeting in 1868 he had begun a movement which resulted in the appointment of a Royal Commission on the advancement of science, chaired by the Duke of Devonshire. One of the recommendations of the Committee stated "Important classes of phenomena relating to physical meteorology and to terrestrial and astronomical physics require observations of such a character that they cannot be advantageously carried on otherwise than under the direction of Government. Institutions for the study of such phenomena should be maintained by the Government; and in particular an observatory should be founded specially devoted to astronomical physics." As Stewart went on to say, the burden on amateur meteorologists was intolerable, "expected to furnish their tale of bricks, they have been left to find their own straw."

Stewart concluded his address by predicting that a great generalisation was looming, a mighty law that would involve facts hitherto inexplicable.

"If Governments would understand the ultimate material advantages of every step forward in science, however inapplicable each may appear for the moment to the wants or pleasures of ordinary life, they would find reasons, patent to the meanest capacity, for bringing the wealth of mind, now lost on the drudgery of common labours, to bear on the search for those wondrous laws which govern every movement, not only of the mighty masses of our system, but of every atom distributed throughout space."

The Association formed committees to investigate various scientific subjects and Balfour Stewart's name appears in exalted company. His interest in energy and heat was shared by men who have come to be regarded as some of the greatest scientists in history. In 1869 Stewart was appointed to a five-man committee to investigate the mechanical equivalence of heat. The other members were Peter Guthrie Tait, professor of natural philosophy at Edinburgh, James Prescott Joule, William Thomson, the future Lord Kelvin, and James Clerk Maxwell. At the meeting in Edinburgh in 1871, there was a report from the committee investigating the rate of increase of underground temperatures; Stewart served on this committee with Thomson, Maxwell and two of the foremost geologists, Sir Charles Lyell and Archibald Geikie.

According to Crosbie Smith in the Oxford Dictionary of National Biography, Stewart, Thomson, Maxwell, Tait and Joule were also linked in the North British network. This was 'an informal group of physicists and engineers, strongly connected with Scotland, that constructed the science of energy in the third quarter of the nineteenth century. Linked by personal friendships, shared scientific interests, and frequent exchanges of correspondence (often addressed from N.B., the abbreviation for North Britain)'.

Balfour Stewart's contact with James Joule wasn't just by correspondence. Joule lived in Manchester and a letter from him to Stewart can be seen online, inviting Stewart to lunch, as Thomson was visiting. They were also both members of the Manchester Literary and Philosophical Society and each in their turn its president.

The Society had been established in 1781. According to its website it is the second oldest learned society in Britain; presumably second only to the Royal Society. It was established 'to promote the advancement of education and the widening of public interest in and appreciation of any form of literature, science, the arts and public affairs'. Before long it had become mainly interested in science because John Dalton, the 'father of modern chemistry' joined the Society in 1794 and remained until his death fifty years later. In 1803 he presented a paper to the society in which he said, "An enquiry into the relative weights of the ultimate particles of gaseous and other bodies is a subject, as far as I know, entirely new; I have lately been prosecuting this enquiry with considerable success." His atomic theory became the foundation of the study of chemistry.

Manchester's involvement in atomic theory is remarkable. As mentioned earlier, J J Thomson, the discoverer of the electron, studied under Balfour Stewart and in 1907 Ernest Rutherford followed Stewart's pupil and successor, Arthur Schuster, as Professor of physics at the university. Rutherford provided the image of the atom being made up of a small dense nucleus surrounded by orbiting electrons and he discovered the proton.

Rutherford grew up in the small town of Nelson, New Zealand and got his first science book when he was ten: Balfour Stewart's Physics primer, written in 1872. This was one of a series of science primers edited by Stewart, Roscoe and Thomas Huxley. In the preface they wrote,

"The object of the Authors has been to state the fundamental principles of their respective sciences in a manner suited to pupils of an early age. They feel that the thing to be aimed at is not so much to give information, as to endeavour to discipline the mind in a way which has not hitherto been customary, by bringing it into immediate contact with Nature herself. For this purpose a series of simple experiments have been devised, leading up to the chief truths of each science. These experiments must be performed by the teacher in regular order before the class. The power of observation in the pupils will thus be awakened and strengthened. "

Stewart wrote the physics primer and his book for adults, Lessons in Elementary Physics, had been published in 1870. He wrote the article on Terrestrial Magnetism for the ninth edition of the Encyclopedia Britannica and many scientific papers but his most widely read book was something entirely different.

Co-written with Peter Guthrie Tait, The Unseen Universe was first published anonymously. Tait had succeeded JD Forbes as professor of physics at Edinburgh (where he taught Charles Anderson from Stenness, future director of the Australian Museum). He did important early work on the science of knots and co-wrote what is described as the seminal energy physics textbook Treatise on Natural Philosophy with Lord Kelvin but his work with Stewart was more controversial.

The Unseen Universe, or Physical Speculations on a Future State, written in 1873, attempted to reconcile science and religion. They wrote,

"We attempt to show that we are absolutely driven by scientific principles to acknowledge the existence of an Unseen Universe, and by scientific analogy to conclude that it is full of life and intelligence - that it is in fact a spiritual universe and not a dead one."

The book was very popular and went into twelve editions. Stewart and Tait put their names to the third and wrote a sequel in 1878, Paradoxical Philosophy.

In Tait's obituary of Balfour Stewart he wrote of the varied responses to The Unseen Universe and went on:-

"Whatever its merits and demerits it has undoubtedly been successful in one of its main objects, viz., in showing how baseless is the common statement that "Science is incompatible with Religion." It calls attention to the simple fact, ignored by too many professed instructors of the public that human science has its limits; and that there are realities with which it is altogether incompetent to deal."

Stewart had played a leading role in ensuring the accuracy of the measurements of those things which could be measured but he also had a deep interest in those things that couldn't be. As well as his strong religious faith, he was interested in psychical research and was a co-founder of The Society of Psychical Research in 1882. It's purpose was to investigate "that large body of debatable phenomena designated by such terms as mesmeric, psychical and spiritualistic" and to do so "in the same spirit of exact and unimpassioned enquiry which has enabled science to solve so many problems".

It would be very interesting to know what role, if any, Balfour Stewart's uncle Rev Charles Clouston played in his early career as a meteorologist. Born in 1800, Charles succeeded his father William as minister of Stromness and Sandwick but was perhaps more interested in the scientific than the spiritual. He founded the Orkney Natural History Society that still runs the Stromness Museum and wrote a guide book to Orkney that includes a list of 156 plants previously unknown in Orkney but his great interest was meteorology. According to the summary of his career in The Church in Orkney,

"Whilst a student in the University of Edinburgh, his attention was directed to the then young science of meteorology, to the advancement of which he particularly devoted his leisure. On his return to Orkney he began a series of observations in regard to the temperature of the Gulf Stream. He followed these up by a number of experiments and investigations in other departments of the science. Among his contributions to the literature of meteorology, were a paper on the meteorology of Orkney, read before the British Association, and which, at the instance of Admiral Fitzroy, was published at the national expense, and a similar paper published in the eighth edition of the Encyclopedia Britannica [edited by Professor Thomas Stewart Traill]; also a small treatise entitled 'Explanations of the Popular Weather Prognostications of Scotland on Scientific Principles'.

Another of his Clouston uncles played a role at the end of Balfour Stewart's life.

Robert Clouston made a fortune in West Africa and really enjoyed spending it. Letters from Germany and Belgium; by an Autumn Tourist was published in 1839 and is now available as a print on demand book from the National Library. The preface describes the book as being made up of letters "written in fulfilment of a promise, made previous to the commencement of the tour they describe, to some friends residing in distant parts of the world; and the writer's intention was simply to communicate to them such information and impressions as he received during the journey."

The letters are full of interesting descriptions and comments on the people and places he saw on a leisurely tour around northern Europe but his greatest interest was art. From Vienna he commented on the contrasting styles of Strauss and Paganini - "His [Strauss's] performance seems, I must confess, somewhat laboured; but, perhaps, this is inseperable from the animated nature of the waltz. It is, however, an extreme contrast to the ease with which Paganini draws out his silvery tones, unlike all that the skill of the world had previously achieved… Strauss is also a composer of no inconsiderable merit and his waltzes never fail to elicit rapturous applause from a Vienna audience. But Clouston admitted he wasn't musical, "It is therefore, better frankly to confess with Mr Jenkins the Cockney - "I am not musical myself, but have a snuff-box that is," and his great love was visiting every art gallery he could find.

Clouston became known as a knowledgeable art collector and was an honorary member of the Royal Institution for the Encouragement of the Fine Arts in Scotland. Three paintings that he donated to the Institution are now at the National Gallery of Scotland; the finest of these, Tiepolo's Finding of Moses is on permanent show there.

Clouston bought land as well as art: his property in Orkney included Northdyke in Sandwick and the Hall of Rendall and he owned an estate in Ireland.

Ballymagarvey is in County Meath, north of Dublin and is now one of Ireland's most exclusive wedding venues. Its website is a bit confused about its history, referring to a Major Coulston who built the very fine stables, but it seems that the manor house and its neighbouring village were built in the very early nineteenth century and added to by Robert Clouston. According to the stone in the cemetery there, he had plenty of time to enjoy his fortune as he died in 1882, aged 84. Balfour Stewart inherited the estate but didn't have so long to enjoy it. He died there at Christmas 1887, aged just fifty-nine.

During his lifetime, Balfour Stewart's work received the recognition it deserved: as well as those already mentioned he received an honorary doctorate from Edinburgh University and has a two page entry in the Oxford Dictionary of National Biography and but very few now would recognise his name. Although his name has not lived on, it is fair to say that his work has, in the influence his teaching and textbooks had on future generations. As was said in the obituary of another Orcadian member of the Royal Society, Dr James Copland, "Gladly would he learn and gladly teach"


Science in Victorian Manchester: Enterprise and Expertise - Robert Hugh Kargon

Predicting the Weather: Victorians and the Science of Meteorology - Katherine Anderson