192 



SCIENTIFIC THOUGHT. 



and as often revived, like that of Prout, 1 on the con- 

 stitution of matter ; the fanciful speculations of Zollner, 

 based upon the views of Wilhelm Weber, all these 

 scattered fragments or glimpses of knowledge promise 

 at the end of the century to come together into a con- 

 sistent theory of the nature of electricity as an atomi- 

 cally - constituted substance which is associated with 

 particles of ponderable matter, or may even be the 

 ultimate constituent of such matter itself. When a 

 large mass of experimental facts and many lines of 

 special reasoning gradually converge towards a common 

 view, two things are indispensable in order to weld them 

 into a consistent whole, viz., a new name or vocab- 

 ulary and an hypothesis as to the elementary processes 

 which will allow of a simple construction and subsequent 

 mathematical calculation of the more complicated phen- 

 omena of actual experience. In the case before us, both 



1 See the concluding chapter of 

 Prof. J. J. Thomson's ' Discharge of 

 Electricity through Gases ' (espe- 

 cially p. 197, &c.), where, after dis- 

 cussing Goldstein's " ether " theory 

 and Crookes's " corpuscular " theory 

 of the nature of the celebrated 

 cathode rays, he, mainly on the 

 strength of his own and Lenard's ob- 

 servations and calculations, inclines 

 towards the latter theory, conclud- 

 ing that the carriers of the negative 

 charges of electricity " are small 

 compared with ordinary atoms or 

 molecules, . . . this assumption 

 being consistent with all we know 

 about the behaviour of these rays." 

 "It may," he continues, "appear 

 at first sight a somewhat startling 

 assumption in a state more sub- 

 divided than the ordinary atom ; 

 but a hypothesis which would in- 

 volve somewhat similar assumptions 



namely, that the so-called ele- 

 ments are compounds of some 

 primordial element has been put 

 forward from time to time by 

 various chemists. Thus Prout be- 

 lieved that the elements were all 

 made up of the atoms of hydrogen, 

 while Sir Norman Lockyer has ad- 

 vanced weighty arguments founded 

 on spectroscopic considerations in 

 favour of the composite nature 

 of the so-called elements. With 

 reference to Prout's hypothesis, 

 if we are to explain the cathode 

 rays as due to the motion of small 

 bodies, these bodies must be very 

 small compared with an atom of 

 hydrogen, so that on this view the 

 primordial element cannot be hydro- 

 gen." See also Sir W. Crookes'a 

 protyle theory referred to, vol. i. 

 p. 402, note 2. 



