THOMSON,J.J. - THE CENTENARY OF HIS DISCOVERY OF THE ELECTRON AND OF HIS INVENTION OF MASS-SPECTROMETRY

Joseph John Thomson (1856-1940), physicist, demonstrated the existence of the electron and, by deflection methods, measured its charge-to-ma ss ratio in 1897. He later applied similar methods to the study of pos itive ions and sorted the constituents of the beams into positive ray parabolas each correspending to a definite ratio of charge-to-mass. As we celebrate the centenary of the measurement of e/m, it is apt to re flect that 'JJT' could be regarded in fact as the pioneer of mass spec trometry, the roots of which can be traced right back to that measurem ent. In a remarkable career, Manchester-born Thomson discovered the el ectron, revealed the existence of the internal structure of the atom a nd laid the foundations of mass spectrometry. As well as being elected a Fellow of the Royal Society, he was awarded the Nobel Prize for Phy sics in 1906 for 'Investigations on passage of electricity through gas es'. One hundred years after his measurement of e/m, it is an appropri ate time to look back on his achievements and to celebrate them in the light of the immense developments which have since taken place in sci ence and, in particular, in mass spectrometry, largely due to his pion eering efforts. (C) 1997 by John Wiley & Sons, Ltd.