WHAT IS MATTER? 35 



many of the lines in the spectra of hydrogen, calcium, iron and other 

 elements are missing when the light from very hot stars is hroken up. 

 For the inference is right at hand, as Professor Bigelow says, " that at 

 extreme, at stellar, temperatures our elements themselves arc disso- 

 ciated into simpler substances." 4 



Further evidence against the atom resulted from Professor J. J. 

 Thomson's studies of cathode rays, strict reasoning from his careful 

 experiments demonstrating them to be swarms of minute particles, or 

 corpuscles, as he called them, moving with velocities approaching that 

 of light, and each weighing about one eight-hundredth as much as a 

 hydrogen atom. These corpuscles are not merely ordinary atoms of 

 smaller bulk, for they do not obey chemical laws, it having been ascer- 

 tained, among other things, that the absorption of them by different 

 substances is simply proportional to the latter's specific gravity, and 

 quite independent of their chemical properties. 



And recently the case against the atom, together with Thomson's 

 ingenious demonstration of his corpuscles, has secured further experi- 

 mental foundation, thanks chiefly to the labors of Becquerel, the 

 Curies, and Eutherford and Soddy, on radioactive substances. These 

 wonderful experiments, at once rapid and reliable, have shown that 

 radioactivity consists in the throwing off of two orders of substances: 

 first, atoms; second, rays or corpuscles of various kinds. But the re- 

 markable fact in the situation is that while the atomic weight of the 

 original substances, radium, thorium and uranium, is two hundred or 

 more, the weight of the atoms thrown off is nearer one or two. That ( 

 is, radium breaks up into, probably, helium, thrown off, and the re- 

 siduum after the emission, which has a different atomic weight from 

 either and is otherwise shown to be a distinct element. 5 The dream 

 of the alchemist has come true and elements are transmuted before our 

 eyes. Science has achieved an unsurpassed triumph ! But, as far as 

 helping us to fortune goes, the dream might as well have remained a 

 dream. 



As a result of these discoveries, and many others similar, in general, 

 in significance, it has come to be admitted that Dalton's atoms are very 

 complex bodies, each made up of a large number of corpuscles, which 

 are related to one another very much as are the members of a planetary 

 system, though in size corpuscles are unimaginably minute, and the 

 number of them constituting any atom is very much larger than the 

 number of members in any planetary system with which we are 

 acquainted. 



4 Popular Science Monthly, July, 1900. 



5 In a communication to Nature, July 18, copied in Science, August 2, Sir 

 Wm. Ramsay states that copper, in the sulphate, acted upon by the emanation 

 from radium, was " ' degraded ' to the first member of its group, namely, 

 lithium." The substance of the quotations that appear later in this paper 

 could be found repeated many times in the writings of Thomson, Ramsay and 

 others of the new school at home and abroad. 



