Aitken, John

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(b. Falkirk, Stirlingshire, Scotland, 18 September 1839; d. Falkirk, 13 November 1919),

engineering, dust, condensation, dew, meteorology.

Aitken was a physicist and meteorologist who worked as a gentleman amateur outside academia. His research, which was experimentally virtuosic but eschewed mathematical formulations, clarified the origins of dew and, most importantly, the role of dust in the formation of cloudy condensations. One of the scientific instruments he invented, the Aitken dust counter, inspired Charles T.

R. Wilson’s work on cloud chamber detectors.

Early Years. John Aitken was born on 18 September 1839 in Falkirk, Stirlingshire, the fourth son of Margaret Russel and Henry Aitken, businessman and head of the legal firm Russel & Aitken. As a young boy, despite persistent ill health, John studied at the Falkirk Grammar School. Like his father and brothers, he then attended the University of Glasgow, taking classes in logic, chemistry, and mathematics in his first year (1855–1856). The following session, while continuing his study of mathematics, Aitken graduated at the top of William J. M. Rankine’s revived class of civil engineering and mechanics—thus preparing himself to support his father, who had a wide portfolio of mining, railway, and shipping interests. That year he also was at the head of William Thomson’s natural philosophy class, establishing a friendship with the professor that endured throughout his life.

After leaving the university in the summer of 1857, Aitken was an apprentice engineer for two years in Dundee, and then for three years (and certainly by 1861) he was in Glasgow as a student with Robert Napier & Sons, prominent Clyde shipbuilders and marine engineers who were closely linked, through James Robert Napier, to both Rankine and Thomson. Surviving drawings of marine steam engines, screw propellers, and paddle wheels (1863–1864) show that Aitken was a consummate draftsman, but a further breakdown in his health forced him to abandon an engineering career. Thus, even though his notes on new safety valves and on an arrangement using two cranks to produce variable motion (supplementing Robert Willis’s science of mechanism) went to the journal Engineering in 1867 and 1868, these were but an amateur’s hints and suggestions, not patented innovations. After the death of both his father and mother (1860) Aitken had become financially secure on inherited wealth, despite having no profession, and by 1867 he had retired to Falkirk, where he lived for many years, unmarried, with his brothers James, Henry, and Robert, lawyer, ironmaster, and clerk, respectively.

Life as a Gentleman Philosopher. Back in Falkirk, Aitken dedicated himself to pursuits suited to a retiring though not reclusive gentlemanly invalid who was permitted only a few hours of work each day: reading, photography, gardening, ornithology, and angling. As he was an intensely religious man, for him such activities, with their emphasis on the divine power present in the everyday phenomena of the natural environment, dovetailed perfectly with painstaking experimental natural philosophy. The latter kept him busy indoors at the family home of Darroch and, from 1897, in his own home Ardenlea: a purpose-built residence with workshop cum laboratory provided with turning lathe, carpenter’s bench, glassware, delicate instruments, and other apparatus Aitken himself had constructed. Although garden and workshop provided flowers for the Falkirk Infirmary and bric-a-brac for charitable re-sale, fulfilling Aitken’s local obligations, nature and laboratory together also represented the merger of outdoor observation and hands-on experimental skill that would become Aitken’s public scientific hallmark.

From 1870 Aitken began to publish extensively, first in professional photographic journals. From 1871 he was a regular contributor to Norman Lockyer’s Nature, over the years sending in papers on sundry topics ranging from butterflies to the economies of the heat-engine regenerator. At the 1871 meeting of the British Association for the Advancement of Science, Aitken met James Clerk Maxwell and discussed color sensation; shortly afterward Aitken’s first major paper, describing experiments that supported a modified form of Young’s three-color theory, appeared before the Royal Scottish Society of Arts (1872). In this work, Aitken had emphasized physiological considerations—such as retinal fatigue—in color perception.

The important work that was to follow concerned ever more precise investigations of the everyday phenomena of nature.

Research in Meteorology. First, Aitken showed how dust was needed for cloudy condensation to take place in naturally occurring circumstances. This work reflected his training by Rankine and Thomson, two founders of classical thermodynamics, and a consequent fascination with the practical conditions of changes of state (notably the melting and freezing of ice (1873). In his “On Dust, Fogs, and Clouds” (December 1880), Aitken showed a rapt audience of Royal Society of Edinburgh Fellows that the condensation of water vapor to form mist, fog, and cloud required the presence of invisible dust particles. Nature publicized Aitken’s results to acclaim: by 1882 they had won the sanction of Lord Rayleigh and, with their extension in a paper “On the Formation of Small Clear Spaces in Dusty Air” (1884), Aitken won the Keith Prize (for 1883–1885) from the Royal Society of Edinburgh. Later he broadened his studies in the production and condensing effects of dust to include the influence of locality, altitude, wind conditions, pressure, time of day, and industry.

A second series of experimental researches settled a centuries-old controversy about the origin of dew: Did it rise from the soil by evaporation, fall from the atmosphere by condensation, or have some other source? In 1885 Aitken reevaluated William Charles Wells’s Essay on Dew(1814), a work praised by John Herschel, the ultimate methodological judge, as a beautiful specimen of inductive experimental inquiry. Through typically minute observations, Aitken concluded that, according to prevailing conditions that he precisely specified, the vapor which condenses as dew on cold surfaces comes mainly from the ground below, not from the air above; thanks to his experiments on broccoli, Aitken could announce, contra Wells, that the so-called dewdrop on leaves of plants is actually exuded sap. Despite vehement criticism from authorities such as Charles Tomlinson, dew—and garden vegetables—helped cement Aitken’s position as a natural philosopher.

Although Aitken was involved in many other areas of scientific study, it was these two pieces of work especially that won him an international reputation as an experimental physicist, even at a time when his lack of enthusiasm for mathematical formulations placed him well outside the British academic mainstream, at least as it was represented by the Cambridge wrangler. Two characteristics of Aitken’;s work illustrate this. The first is the use of instruments that he designed and often made himself. The chromomictor (1885) recalled his earliest significant work, using lenses and a camera obscura rather than conventional rotating disks to mix lights of different colors for experiments in physiological optics.

Most famous, however, were his various dust counters. Because condensation normally required dust, the number of droplets of water falling onto a silvered surface as saturated air was slightly expanded would indicate the number of particles. By 1889 Aitken had created a heavy-duty form, requiring a complex housing, suitable for a first-class laboratory; a simple pocket dust counter was available by 1890. The koniscope, or dust detective, (1892) used an optical technique to gauge the concentration of dust in air. Aitken regularly exhibited both koniscope and pocket dust counter (for example, at the British Association meeting at Nottingham in 1893), and it was left to the Edinburgh instrument maker William Hume, a man active in the Royal Scottish Society of Arts and in the distribution of kits for experimental physics classes and public health laboratories, to manufacture, market, and further develop the apparatus into the early twentieth century.

Aitken made wide use of the portable counter himself: partly for his health and partly to gather data. He made excursions within Scotland (often to the holiday resort of Kingairloch), ascended Swiss peaks, and, even before its public opening in 1889, sampled the air at the top of the Eiffel Tower in Paris. During 1894–1895 Frid-lander had carried Aitken’s dust counters around the globe, charting prevalence of dust particles in the great oceans far from land. Others were stationed in the Sahara (1897) to correlate dust with precipitation.

The second characteristic was best illustrated in Aitken’s discussions of the dynamics of cyclones and anticyclones, begun in 1900 but still causing a stir as late as 1916. Rather than deploy the abstruse mathematical models that were likely beyond him, Aitken simply imitated on a large experimental scale within his laboratory the production and movement of the cyclone itself. His apparatus deployed a large vertical metal tube standing on three legs above a disk three times the tube’s diameter. Gas burners mounted inside the tube created an up-draught; vanes, or chemical fumes, showed the direction of the circulation of the affected air. This process of mimicry, reducing macroscopic phenomena to manageable laboratory scale, was adopted by many contemporary British physicists. Conscious of British neo-Baconian traditions, Aitken developed strategies to avoid mathematical theorizing when he conceived it to be merely fashionable, premature, or downright dubious. He prided himself on the fact that his “test tube kind of work” could discredit the assumptions of “mathematical workers” (Aitken to Smithells [14 July 1917).] Significantly, his library lacked Newton’s Principia Mathematica but contained works by the archetypical experimenters Robert Boyle and Michael Faraday: well read in his chosen fields, his indifference to scientific orthodoxy when close observation (or effective laboratory mimicry) challenged it allied him to the early Royal Society’s motto: “nullius in verba,” ironically, Newton’s motto.

Perhaps this was the reason that Aitken’s enthusiasms centered increasingly on meteorological questions. From 1884 until his death he took a particular interest in the accurate measurement of air temperature, criticizing in particular the use of Thomas Stevenson’s thermometer screen, a standard piece of apparatus despite its unreliability in hot climates. He recorded weather data at home systematically and with precision for many years. From 1890 two Aitken dust counters—one self-acting, one portable—could be found alongside the other recording instruments central to the observational regime of the permanently staffed Ben Nevis Meteorological Observatory. Designed by Stevenson and opened in 1883, the observatory at the summit of Britain’s highest mountain was the prestige project of the Scottish Meteorological Society (founded in 1855), and as both founding donor and one of a team of directors (through the 1890s) Aitken served beside elite scientific representatives of the Royal Societies of Edinburgh and London.

Intriguingly, the talented student Charles Thomas Rees Wilson, who was trained at Cambridge University and the Cavendish Laboratory, took a summer job at the observatory in 1894, witnessed Aitken’s instruments, and went on to extend the original dust counters to create an apparatus, later known as a cloud chamber, capable of tracking not dust particles but ions. Wilson (and Aitken before him) had seen that in more extreme circumstances than those normally occurring in nature (with considerable rates of expansion and cooling of saturated air), cloudy condensation formed in dustless air around electric ions. Wilson published his work in 1895, ultimately receiving the Hughes Medal of the Royal Society of London (1911). J. J. Thomson’s classical experiments of the late 1890s on the mass and charge of the electron (later so called) effectively extended Aitken’s technique: Thomson deployed Wilson’s idea to detect and count charged prticles in dust-free air. Thus the dust counter had a new life in the world of particle physics.

Aitken’s work won widespread recognition from individuals and institutions alike. He gravitated from the Royal Scottish Society of Arts, which he had joined in December 1871, to become a Fellow of the Royal Society of Edinburgh (RSE) in April 1875, supported by three reform-minded Glasgow University professors: Allen Thomson (anatomy), James Thomson (engineering), and William Thomson (Lord Kelvin; natural philosophy). The work of the last of these, on vortex atoms, received indirect support soon after from Aitken’s experiments (December 1875) on the rigidity produced by centrifugal force. Thereafter the RSE became Aitken’s chief outlet for his many publications. But in June 1889 he became a Fellow of the Royal Society of London, again with the support of James and William Thomson, and with his reputation as a philosopher of dust, profound observer, and ingenious instrument designer running high. Although Aitken was happy to discourse upon the romance of dust before the ladies at a Royal Society of London conversazione shortly after his election, he shied away from senior office in these scientific institutions on health grounds (although, characteristically, he did hold the office of honorary president in the local Falkirk Natural History and Archaeological Society).

Aitken also received numerous distinctions, including the Gunning Victoria Jubilee Prize of the Royal Society of Edinburgh for his work in the physics of meteorology (for the period 1893–1896, awarded 1897), an honorary LLD from the University of Glasgow (1902), and a prestigiou Royal Medal from the Royal Society of London in recognition of his lifelong researches on the nuclei of cloudy condensations (1917). Appropriately, he was awarded Gold Medals for his instruments, including the portable and pocket dust counters and the koniscope, when they were exhibited at the Franco-British Exhibition of 1908.

Aitken died at Ardenlea on 13 November 1919, at the age of eighty, and was buried in the Falkirk Cemetery five days later. His scientific investigations had left him unconvinced by spiritualism, impervious to T. H. Huxunconvicey’s agnosticism and religiously devout to the end. As one of Falkirk’s richest citizens and a constant philanthropist and humanitarian, he left half of his estate of nearly £100,000 to his local community, establishing a “temperance café” to promote the moral improvement of local workers, and the rest as a fund for the poor of Falkirk. The Universities in Edinburgh and Glasgow shared the scientific apparatus he offered them jointly in his will. The Royal Society of Edinburgh accepted the money he left for a posthumous monument (to himself) in the form of a collection of his papers. The editor and meteorologist C. G. Knott knew well that Aitken had labored long and hard to “elucidate the workings of Nature in her everyday moods” (Nature [27 November 1919]: 338).


Falkirk Council Archives has Aitken’s papers, including engineering drawings, experimental notebooks, draft articles, meteorological records, and domestic records (c. 1863 until his death) in the Russel & Aitken WS Papers supplemented by Dep. 240 (formerly National Library of Scotland). Correspondence with James Clerk Maxwell, George Gabriel Stokes, Sir Joseph John Thomson, and William Thomson (Lord Kelvin) is in Add. 7655, Add. 7656, Add. 7654 and Add. 7342, respectively, in Cambridge University Library. There is an additional letter to William Thomson (Lord Kelvin) in MS Kelvin A4, Glasgow University Library. Material relating to Aitken and the Royal Scottish Society of Arts (Acc. 4534) and the Royal Society of Edinburgh are in the National Library of Scotland. The Brotherton Library at the University of Leeds has letters from Aitken and Arthur Smithells (MS 416). There is a letter to William Fletcher Barrett in Barrett’s papers at the Royal Society of London. Original instruments can be found in the Royal Museum of Scotland (NMS T1983.125) and in the Science Museum, London (1908-193).


Collected Scientific Papers of John Aitken, LL.D., F.R.S. Edited by Cargill G. Knott. Cambridge, U.K.: Cambridge University Press for the Royal Society of Edinburgh, 1923. This is the key collection, with an introductory memoir superseding or synthesizing the contemporary obituaries (many of which Knott had provided). There is an extended, if incomplete and not wholly reliable, bibliography. Since Knott edited the papers extensively, it is advisable to check the originals.


Clarke, Tristram N., Alison D. Morrison-Low, and Allen D. C. Simpson. Brass and Glass: Scientific Instrument Making Workshops in Scotland. Edinburgh: National Museums of Scotland, 1989. For information on Aitken’;s association with Edinburgh instrument maker William Hume, see pp. 133–137.

Galison, Peter. Image and Logic: A Material Culture of Microphysics. Chicago: University of Chicago Press, 1997 (esp. pp. 81–96). On cloud formation experiments, the dust chamber, mimetic experiments, meteorology and relationship with C. T. R. Wilson.

———, and Alexi Assmus. “Artificial Clouds, Real Particles.” In The Uses of Experiment: Studies in the Natural Sciences, edited by David Gooding, Trevor Pinch, and Simon Schaffer. Cambridge, U.K., and New York: Cambridge University Press, 1989. Aitken’s mimetic experiments in physics and, especially, C. T. R. Wilson.

Podzimek, Josef. “John Aitken’s Contribution to Atmospheric and Aerosol Sciences: One Hundred Years of Condensation Nuclei Counting.” Bulletin of the American Meteorological Society 70 (1989): 1538–1545.

Roy, Marjory. The Weathermen of Ben Nevis, 1883–1904. London: Royal Meteorological Society, 2004. On the Aitken dust counter as a meteorological instrument.

Ben Marsden