During his career he held academic posts at the universities of University of Manchester (1951–6), Durham University (1956–92), the University of Ceylon and the University of Hong Kong, and was head of department at Durham where he remains an emeritus professor.
After returning to Ceylon Appapillai collaborated with Blackett, Arnold Wolfendale and A. W. Mailvaganam in establishing that Associated Penetrating Particles did not exist within the limits of measurement.
Arnold Schwarzenegger | Arnold Schoenberg | Benedict Arnold | Arnold Palmer | Arnold Bax | Matthew Arnold | Eddy Arnold | Hey Arnold! | Henry H. Arnold | David Arnold | Arnold Wesker | Thomas Arnold | Arnold Toynbee | Arnold Rothstein | Arnold Friberg | Arnold Dreyblatt | Arnold Bennett | Arnold Sommerfeld | Richard R. Arnold | Arnold Moss | Arnold Fanck | Arnold Böcklin | Arnold Arboretum | Arnold | Johnny Arnold | Frances Arnold | Arnold Zweig | Arnold Vosloo | Arnold Rüütel | Arnold Rimmer |
The observatory was officially opened on the 25 April 2008 by Sir Arnold Wolfendale 14th Astronomer Royal.