Elected: 1970
Discipline: Physics and Astronomy
Professor Charles William McCombie FRSE
Charles McCombie was born in Monifieth, Angus, in September 1926. He was fortunate to be brought up in a close family where his parents, recognising his ability and the value of a good education, gave him constant encouragement. He won a place at Robert Gordon’s College, Aberdeen, where he gained many distinctions culminating with the award of top place in his home town’s University Bursary Competition. Charles was an undergraduate at the University of Aberdeen from 1944 to 1948, initially intending to take a degree in Chemistry but switching to Mathematics and Natural Philosophy at the end of his second year.

After graduating with First Class Honours in 1948 he continued in Aberdeen as a research student supervised by Professor R. V. Jones. He started on a project in solid state physics but was soon diverted into providing the theoretical analysis to back up his supervisor’s experimental study of methods of enabling detectors to achieve close to the ultimate limit of accuracy set by inevitable thermal fluctuations. The detector studied was a simple galvanometer and, in order to detect the small displacements of the optical lever spot corresponding to these fluctuations, an ingenious amplification system involving a pair of back-to-back photocells in the circuit of a second galvanometer was designed. The analysis of the galvanometer amplifier became McCombie’s Ph.D. project and, as is almost always the case, the crucial ideas in his thesis formed an important part of the intellectual machinery that he was to make use of in subsequent work: in his case the key element was the relation between damping and the fluctuating forces that operate on a system as it oscillates around thermal equilibrium. He extended his Ph.D. work in an important and substantial review of Fluctuations and Physical Measurement published in Reports on Progress in Physics.

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