370 



SCIENCE. 



[N. S. Vol. XII. No. 297. 



but the charged ions performed the same 

 duty of allowing condensation to begin, and 

 hence the number of water drops is the same 

 as the number of ions present in the air. 

 To count the number of drops, the weight 

 of the cloud is determined by a sensitiye 

 balance. They are also allowed to settle in 

 a bell jar, and the rate of settling is ob- 

 served. The calculations of Stokes, based 

 upon the viscosity of air, show at what rate 

 drops of different size will fall, and from 

 this, the size of the water drops is deter- 

 mined. The size of the drops and the 

 weight of the cloud give the total number 

 of drops in the cloud, and hence the num- 

 ber of ions present in the air. 



The result of this experiment turns out to 

 be that the number of ions, carrying a unit 

 quantity of electricity is perhaps a little less, 

 certainly not very different, from the num- 

 ber carrying a unit quantity in the case of 

 solutions. The other alternative seems to 

 be the true one, that the mass of each ion 

 (or ' corpuscle ' as Thomson calls them) has 

 about ytjVtj the mass of the hydrogen atom. 

 More than this, it seems to be the same for 

 all the gases tried, instead of differing with 

 their atomic weight, indicating that all these 

 gases give off corpuscles of the^same mass. 



These results, revolutionary as they are, 

 fit in well with some other facts. Thus, the 

 stream of electrified particles constituting 

 the cathode ray, is found to penetrate a mass 

 of air much farther than would be expected 

 if the ray were composed of particles as large 

 as atoms, but just about as far as if they 

 were -^-^-^-^ as large as hydrogen atoms. 

 They also penetrate all gases in the inverse 

 ratio of their densities. However, if the 

 reason for this is to be found in the fact that 

 their molecules are all built up of corpuscles 

 of the same kind, it must also be true that 

 the structure of the molecules is extremely 

 porous, allowing the corpuscles to pass 

 through them with great freedom. 



Further confirmation of this theory is 



found in a recent discovery by Zeeman in 

 spectrum analysis. When a luminous gas is 

 between the poles of an electromagnet, the 

 lines of its spectrum are found to be affected 

 in such wise as to indicate that the parti- 

 cles whose vibrations produce the light are 

 electrified ; and the ratio of the charge to 

 the mass of the particles is found to be the 

 same as for Thomson's ' corpuscles.' Men- 

 deleef, who has grouped the chemical ele- 

 ments into a remarkable series of families, 

 says " the periodic law together with the 

 revelations of spectrum analysis, have con- 

 tributed again to revive an old, but remark- 

 ably long-lived hope, that of discovering 

 * * * the primary matter, which had its 

 genesis in the minds of the Grecian philoso- 

 phers, and has been transmitted, togethe^" 

 with many other ideas of the classic period, 

 to the heirs of their civilization." " From 

 the failures of so many attempts at finding in 

 experiment and speculation, a proof of the 

 compound character of the elements, and of 

 the existence of primordial matter, it is evi- 

 dent, in my opinion, that this theory must 

 be classed among mere Utopias." 



It would seem that a beginning has been 

 made in attaining this Utopia. The theory 

 is too new and too extreme to have received 

 the scrutiny and the criticism which it de- 

 serves. It yet remains to be seen whether 

 it is consistent with the low internal energy 

 of gaseous molecules, or whether it will 

 prove valuable in explaining the electrical, 

 magnetic or chemical properties of bodies. 

 Its author has already published a number 

 of suggestive ' speculations ' as to the part 

 played by corpuscles in electrical and heat 

 conduction, in the Thomson effect, in the 

 magnetism of rotating matter (terrestrial 

 magnetism ?) and in a number of the other 

 electrical properties of bodies, which at least 

 indicate some of the possibilities of the new 

 theory in the domain of molecular phj^sics. 

 Charles A. Perkins. 



University of Tennessee. 



