In 1937, he was appointed Lecturer in Electrical Engineering at University College, Swansea until called away to war service in the scientific civil service. Here he first extended the chain-home radars to detect low flying targets. He subsequently met with Churchill's scientific adviser, R V Jones, and assisted in detecting the signals from the enemy navigator aids used to direct bombers on to target. Farvis led the interception group, with Martin Ryle in charge of the associated radio jamming group, all coordinated by Robert Cockburn. One of Farvis’ major wartime achievements was to counteract a sophisticated new Germannavigation aid, "Benito", with Alex Harley Reeves, the later inventor of pulse code modulation telephony. Farvis went to London with the new radio jammer and, on listening to the German bombers’ radio telephone traffic, he noted that they suspected equipment malfunction, rather than intentional jamming. After the war, Farvis debriefed these German equipment designers. Academic appointments at The University of Edinburgh followed in 1948 as a lecturer in Applied Electricity. Here his research focussed on the then fashionable topic of gaseous electronics. He was closely associated in ionospheric research with Edward Appleton when he was University Principal. In 1961, Farvis became the first Professor and Head of the new Department of Electrical Engineering. Following this, his interests moved into the rapidly expanding field of solid-state electronics. In 1964 he took the bold move to construct a centre for solid-state devices and materials science research at Edinburgh and constructed the first university cleanrooms for silicon semiconductor device fabrication. he was an early pioneer in identifying the significance of semiconductor transistors for application in future electronic systems. In 1969 Farvis set up of the Wolfson Microelectronics Liaison Unit, coinciding with the first appointment of part-time paid visiting Professors in a UK university. WMLU later expanded into an independent company, Wolfson Microelectronics, under Professor David Milne before being acquired by Cirrus Logic. Many of his post-war innovations in the undergraduate curriculum were tried out at Edinburgh before catching on elsewhere, including: open book examinations; individual experimental project work and in-depth dissertation writing. He was innovative in moving the final honours’ examinations from June to January, to improve the student focus on project work.
