184 



CHAP. XXIV. INORGANIC EVOLUTION FROM A PHYSICAL STAND- 

 POINT. 



THE next question which arises is whether there is any way open to 

 us of getting still more light on this matter beyond that furnished by 

 orthodox chemistry. 



With the progress of science the idea of " atoms " has considerably 

 changed. 



Formerly they were regarded as merely chemically different from 

 element to element ; the recent investigations have introduced a new 

 conception. It is now no longer chemically different matter merely, 

 but matter, whether chemically different or not, carrying an electric 

 charge. In the first work along this new line, physicists, in order to 

 grapple with the phenomena of electrolysis and solutions, imagined 

 sub-molecules or sub-atoms carrying an electric charge in an electrolyte 

 from the anode to the cathode ; this was called an ion (Gr. a goer). 

 This conception has been more recently used to explain those move- 

 ments of particles of matter which produce light, and therefore spectral 

 lines. The sub-particle, this ion, with its electric charge e and its 

 mass ra, is supposed to move in an elliptic orbit under the attraction 

 of a centre. At first the theory supposed the ions to be electrified par- 

 ticles, but a recent extension considers them to be complex dynamical 

 systems, the motions of which are registered by spectral phenomena. 



It will be gathered from what I have already said relating to the 

 various questions connected with the study of " series " of spectral 

 lines how the idea of " complex dynamical systems " is also demanded 

 to explain the phenomena presented by them. 



Thus I have shown it to be probable that the hydrogen atom which 

 the chemist weighs may be built up of hundreds of the things, call 

 them what you will, a few of which in the hottest stars produce the 

 vibrations which we take as demonstrating the existence of hydrogen 

 in the celestial spaces. 



Both these lines of modern evidence tend to justify the view that 

 the different spectra are not produced by different material, but by 

 different conditionings of the same material. 



These different conditionings may refer either to the electric charge 

 or to the mass of the ion, or of the molecule round which the ion cir- 

 culates. The units of matter present in the ion or in the central 

 molecule may vary in number, or their arrangement may vary. 



