Every Cloud has a Silver Lining

Charles Thomson Rees Wilson

Scotland’s mountains and glens have motivated countless people over the years, from famous writers and artists, to ordinary folk whose inspiration may not be documented in words and pictures but is every bit as profound, albeit on a more personal level.

The country’s wild land has prompted a profusion of poems, stories and paintings. But romance, literature and artistic masterpieces are not the only products of outdoor musing. Academic inspiration has also been drawn from the mountains and nowhere is this more evident than in the work of Charles Thomson Rees Wilson, Scotland’s only winner of the Nobel Prize for Physics.

It was Britain’s highest mountain, Ben Nevis, which inspired the brilliant young scientist to excel in his field. Had it not been for a two week stay at the summit observatory during the summer of 1894, he may very well have settled for the security of a career as a school teacher. Instead the mountain changed his life, Wilson himself directly linking his award-winning work with his time at the observatory and the sights he witnessed.

He opened his Nobel Lecture of December 12, 1927 with the words: ‘In September 1894 I spent a few weeks in the observatory which then existed on the summit of Ben Nevis, the highest of the Scottish hills. The wonderful optical phenomena shown when the sun shone on the clouds surrounding the hill-top, and especially the coloured rings surrounding the sun or surrounding the shadow cast by the hill-top or observer on mist or cloud, greatly excited my interest and made me wish to imitate them in the laboratory.’

He later wrote: ‘The whole of my scientific work undoubtedly developed from the experiments I was led to make by what I saw during my fortnight on Ben Nevis.’

Born at Crosshouse in the Pentlands in 1896, Wilson was at a crossroads in his life when he applied for a post at the summit observatory. From an early age he had been fascinated by science and, in 1888, he secured a scholarship to study at Cambridge’s Sidney Sussex College. He initially set his sights on a career as a physician and studied biology but soon abandoned medicine in favour of physics, completing his degree in 1892.
Wilson was also a keen mountaineer and regularly travelled north to Scotland to climb and he clearly relished the prospect of exploration, writing: ‘I might be of use as an explorer as I have powers of endurance tested on the Scottish hills.’

Despite this enthusiasm, he settled for a job as a grammar school teacher. But the desire to explore was never very far from Wilson’s thoughts and when the opportunity to go to Ben Nevis arose he grabbed it.

Ben Nevis from the tourist path

The summit observatory had been in operation for several years by this stage, having opened in 1883. Hourly meteorological readings were made and recorded throughout the year by three permanent observers. During the summer months the Scottish Meteorological Society employed young physicists to relieve the full-time weathermen and Wilson secured a two-week stint in September 1894.

He travelled north to Fort William and ascended the path to the top, built to service the observatory and now the popular ‘tourist route’ taken by the majority of hill walkers who ascend the mighty peak.

By the time Wilson visited significant improvements had been made to the facility. When it was originally constructed, the observatory consisted of just one squat room, 13-feet square with stone walls which were up to 12-feet thick. Conditions were far from ideal and, after a particularly bad first winter when the weathermen were frequently trapped inside by deep snow drifts and had to dig their way out, an office/laboratory, two bedrooms, a visitors’ room and a 30-foot tower were added.

Wilson was put to work gathering readings from the barometer, various thermometers and a rainfall gauge. He noted cloud cover, wind speed and direction, and hours of sunlight. Records for the time indicate he enjoyed reasonably good conditions during his stay, with plenty of sunshine.

What proved to be of most interest to the young scientist, however, were the various atmospheric phenomena he saw. Among these was the beautiful Brocken Spectre, an optical occurrence involving cloud and sunlight which is witnessed at altitude, usually by mountaineers or aircraft passengers. Observers see coloured rings surrounding the sun, known as ‘coronas’, or surrounding their shadow or the shadows of other objects on mist or cloud, known as ‘glories’. Entranced by these visions, Wilson determined to find out how they were formed.

With new direction in his life, he returned home and took a job at Cambridge University demonstrating the principles of physics to students. There he had access to the world renowned Cavendish Laboratory where he started to conduct his own experiments in a bid to explain the coronas and glories.

He already knew how clouds formed, thanks to the work of fellow Scottish scientist John Aitken, of Falkirk, who discovered they stemmed from water droplets gathering around particles of dust. Wilson made his own apparatus in which to create small clouds under controlled conditions for his experiments, even going to the extent of carefully blowing his own glass chambers.

He stated in his Nobel Lecture: ‘Almost immediately I came across something which promised to be of more interest than the optical phenomena which I had intended to study.’

The ruins of Ben Nevis observatory

Wilson was talking of his new cloud chamber which enabled him to undertake ground-breaking early research into atoms and radioactivity. In 1911 he succeeded in photographing the tracks of particles and electrons. His work on the Wilson Cloud Chamber continued until he finally perfected the apparatus in 1923. Papers on the tracks of electrons followed and, in 1927, Wilson was awarded the Nobel Prize.

The cloud chamber enabled scientists to study the paths of electrically charged particles and it became vital to the study of radioactivity and the development of nuclear physics. It was hailed as a major breakthrough in the development of scientific study.

By this stage Wilson was Jacksonian Professor of Natural Philosophy at Cambridge, a post he held from 1925 to 1934. His interest in the skies above continued throughout his career and he went on to study cosmic rays and atmospheric electricity. His studies of thunderstorms led him to devise a way of protecting wartime barrage balloons and he published his last scientific paper, on the theory of thundercloud electricity, at the age of 88.

He continued to climb and spend time in the mountains of Scotland right into his 80s and, having retired to Edinburgh and then the village of Carlops, near Penicuik, retained a particular passion for the hills of Arran, ascending Caisteal Abhail, above Glen Sannox, at the age of 82.

While Wilson carved out a distinguished career for himself, the place where it all began, the Ben Nevis Observatory, was rather less fortunate. A lack of funding forced closure in October 1904, although the building remained in use until 1916, offering shelter and refreshments to climbers and visitors during the summer months. Slow decline, peppered by a fire and vandalism, followed and by the late 1970s the building was finally dismantled. Now all that remains of this brave Victorian scientific enterprise are some ruins and a plaque.

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