Counting dust and domesticating clouds: inside the âoutdoor physicsâ of John Aitken

This paper takes the work of John Aitken, physicist and meteorologist, to illustrate one facet of nature on display in late nineteenth-century Scotland. Commentators on Aitken from the early twentieth century classified him as a devotee of âoutdoor physicsâ. They recognised his profound spiritual engagement with everyday environmental phenomena, understanding that his explanations of dew or clouds according to scientific canons did not diminish his wonder at nature. Here, I re-consider Aitkenâs programme of reducing complex phenomena on the largest natural scale, whether a beautifully coloured sky or a vast weather system, to the scope of his domestic workshop laboratory. Trained as an engineer, Aitken used mechanical skills to manufacture models of glaciers or anti-cyclones at home. In a process of small-scale âmimicryâ, models provided suggestive analogies to natural phenomena, from which scientifically useful inferences could be made. It was a scientific style intermediate between the reductive, analytical practices of the physical laboratory and the observation of untamed natural phenomena. In an age of âBig Scienceâ, with international involvement and costs beyond the reach of the individual, Aitken prided himself on what he called a âtest-tube kind of workâ, devoid of mathematical complication; he nevertheless won a prestigious Royal Medal from the Royal Society of London. For Aitken, glaciers and clouds alike could be reduced to homely demonstrations fit for gentlemanly entertainment