<P> Between 1838 and 1851, British natural philosopher Richard Laming developed the idea that an atom is composed of a core of matter surrounded by subatomic particles that had unit electric charges . Beginning in 1846, German physicist William Weber theorized that electricity was composed of positively and negatively charged fluids, and their interaction was governed by the inverse square law . After studying the phenomenon of electrolysis in 1874, Irish physicist George Johnstone Stoney suggested that there existed a "single definite quantity of electricity", the charge of a monovalent ion . He was able to estimate the value of this elementary charge e by means of Faraday's laws of electrolysis . However, Stoney believed these charges were permanently attached to atoms and could not be removed . In 1881, German physicist Hermann von Helmholtz argued that both positive and negative charges were divided into elementary parts, each of which "behaves like atoms of electricity". </P> <P> Stoney initially coined the term electrolion in 1881 . Ten years later, he switched to electron to describe these elementary charges, writing in 1894: "...an estimate was made of the actual amount of this most remarkable fundamental unit of electricity, for which I have since ventured to suggest the name electron". A 1906 proposal to change to electrion failed because Hendrik Lorentz preferred to keep electron . The word electron is a combination of the words electric and ion . The suffix - on which is now used to designate other subatomic particles, such as a proton or neutron, is in turn derived from electron . </P> <P> The German physicist Johann Wilhelm Hittorf studied electrical conductivity in rarefied gases: in 1869, he discovered a glow emitted from the cathode that increased in size with decrease in gas pressure . In 1876, the German physicist Eugen Goldstein showed that the rays from this glow cast a shadow, and he dubbed the rays cathode rays . During the 1870s, the English chemist and physicist Sir William Crookes developed the first cathode ray tube to have a high vacuum inside . He then showed that the luminescence rays appearing within the tube carried energy and moved from the cathode to the anode . Furthermore, by applying a magnetic field, he was able to deflect the rays, thereby demonstrating that the beam behaved as though it were negatively charged . In 1879, he proposed that these properties could be explained by what he termed' radiant matter' . He suggested that this was a fourth state of matter, consisting of negatively charged molecules that were being projected with high velocity from the cathode . </P> <P> The German - born British physicist Arthur Schuster expanded upon Crookes' experiments by placing metal plates parallel to the cathode rays and applying an electric potential between the plates . The field deflected the rays toward the positively charged plate, providing further evidence that the rays carried negative charge . By measuring the amount of deflection for a given level of current, in 1890 Schuster was able to estimate the charge - to - mass ratio of the ray components . However, this produced a value that was more than a thousand times greater than what was expected, so little credence was given to his calculations at the time . </P>

Who discovered that electrons have a negative charge