

The Stratifications of Hydrogen. 411 



expression " Radiant Matter," or matter in the ultra-gaseous state, 

 to explain the novel phenomena of phosphorescence, trajectory, 

 shadows, mechanical action, magnetisation, and intense heat. " In 

 studying this fourth state of matter," I said, " we seem at length 

 to have within our grasp and obedient to our control, the little 

 indivisible particles which with good warrant are supposed to con- 

 stitute the physical basis of the universe. We have seen that in 

 some of its properties radiant matter is as material as this table, 

 whilst in other properties it almost assumes the character of radiant 

 energy. We have actually touched the borderland where matter 

 and force seem to merge into one another."* 



In twenty-five years one's theories may change, although the 

 facts on which they are based remain immovable. What I then 

 called " Radiant Matter " now passes as " Electrons," a term coined 

 by Dr. Johnstone Stoney, to represent the separate units of elec- 

 tricity, which is as atomic as matter. What was puzzling and unex- 

 plained on the " Radiant Matter " theory is now precise and luminous 

 on the " Electron " theory. Thus my early hypotheses fall into order 

 by the substitution of one expression for the other. A chemical ion 

 consists of a material nucleus or atom of matter constituting by far 

 the larger portion of the mass, and a few electrons or atoms of elec- 

 tricity. The electrons are the same as the "satellites" of Lord 

 Kelvin and the " corpuscles " or " particles " of J. J. Thomson. 



Electrons probably leave the negative pole with a velocity nearly 

 uniform, modified to a considerable extent by the degree of exhaustion, 

 and to a less extent by the electromotive force behind them. Many 

 experiments the details I must leave to a future occasion show 

 that the liberated electrons do not behave as a gas, >., they have not 

 properties dependent on inter-collisions, mean free path, &c. ; they act 

 more like a fog or mist, are mobile and carried about by a current 

 of air to which they give temporary conducting powers, clinging to 

 positively electrified bodies and thereby losing mobility, and settling 

 on the walls of the containing vessel if left quiet. 



On the other hand, the crowd of hydrogen or mercury atoms, by 

 virtue of molecular motion and inter-collisions, act as gases. Whilst 

 their mean free paths are conditioned by the degree of exhaustion, there 

 may be amongst them a certain numlxjr of actwil free paths differing 

 widely on each side of the mean. Under the influence of the electro- 

 motive force, and at the right degree of exhaustion, these atoms 

 arrange themselves in groups,! while the rushing swarm of electrons 



* ' Chemical News,' vol. -AO, p, 130. 



t In an address delivered before the Institution of Electrical Engineer*, 

 January 15th, 1891, I gave an outline of a theory of stratifications in rarefied gases. 

 The following quotation renders my meaning clear : " If, in any much fre- 

 quented street, at some time when the stream of traffic runs almost equally in both 

 directions, we take our stand at a window from which wo can overlook the passing 



