In 1897[2] he discovered the Anomalous Zeeman Effect, a phenomenon noted when the spectral lines of elements were studied in the presence or absence of a magnetic field.
Following this up further, he reported in a second paper in the RDS Scientific Transactions, read on 18 January 1899, and published the following June, that he had found results that were ’very startling’ and appeared ‘quite contrary to all theoretical explanations’.
The full explanation had to wait for the theory of relativity and the introduction of quantum mechanics, which were to shake the rigid framework of Newtonian conceptions of absolute time and space.
Preston famously tackled Stoney in what became a public dispute over a mathematical conclusion in this research programme which concerned electromagnetic and spectroscopic sciences.
[6] He died at his home, Bardowie, Orwell Park, Rathgar, Dublin, on 7 March 1900 of a perforated ulcer just as he was reaching the height of his academic powers.