Kaufmann[91] and Simon[92] used a different method to determine the value of _e_/_m_. The potential difference _V_ between the terminals of the tube was measured. The work done on the charged particle in moving from one end of the tube to the other is _Ve_, and this must be equal to the kinetic energy 1 -- _mu²_ 2 acquired by the moving particle. Thus _e_ _u²_ --- = ---- (3). _m_ 2_V_ By combination of this equation with (2) obtained by measurement of the magnetic deflexion, both _u_ and _e_/_m_ can be determined. Simon found by this method that _e_ --- = 1·865 × 10⁷. _m_ It will be seen later (section 82) that a similar value was deduced by Kaufmann for the electrons projected from radium. These results, which have been based on the effect of a magnetic and electric field on a moving ion, were confirmed by Weichert, who determined by a direct method the time required for the particle to traverse a known distance. The particles which make up the cathode stream were termed “corpuscles” by J. J. Thomson. The name “electron,” first employed by Johnstone Stoney, has also been applied to them and has come into general use[93]. The methods above described do not give the mass of the electron, but only the ratio of the charge to the mass. A direct comparison can, however, be made between the ratio _e_/_m_ for the electron and the corresponding value for the hydrogen atoms set free in the electrolysis of water. Each of the hydrogen atoms is supposed to carry a charge _e_, and it is known that 96,000 coulombs of electricity, or, in round numbers, 10⁴ electromagnetic units of quantity are required to liberate one gram of hydrogen. If _N_ is the number of atoms in one gram of hydrogen, then _Ne_ = 10⁴. But if _m_ is the mass of a hydrogen atom, then _Nm_ = 1. Dividing one by the other _e_/_m_ = 10⁴. We have seen already that a gaseous ion carries the same charge as a hydrogen atom, while indirect evidence shows that the electron carries the same charge as an ion, and consequently the same charge as the atom of hydrogen. Hence we may conclude that the apparent mass of the electron is only about ¹⁄₁₀₀₀ of the mass of the hydrogen atom. The electron thus behaves as the smallest body known to science.