Joseph John Thomson (1856Thomson ( -1940)), physicist, demonstrated the existence of the electron and, by deflection methods, measured its charge-to-mass ratio in 1897. He later applied similar methods to the study of positive 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 reflect that 'JJT' could be regarded in fact as the pioneer of mass spectrometry, the roots of which can be traced right back to that measurement.
In a remarkable career, Manchester-born Thomson discovered the electron, revealed the existence of the internal structure of the atom and laid the foundations of mass spectrometry. As well as being elected a Fellow of the Royal Society, he was awarded the Nobel Prize for Physics in 1906 for 'Investigations on passage of electricity through gases'. One hundred years after his measurement of e/m, it is an appropriate time to look back on his achievements and to celebrate them in the light of the immense developments which have since taken place in science and, in particular, in mass spectrometry, largely due to his pioneering efforts.