ARE THE ELEMENTS TR AN SMUT ABLE? 43 



other lines belonging in the same series may be calculated. In this 

 way the positions of certain lines for certain elements were foretold. 

 Search failed to reveal all of them in light emitted by the element at 

 any temperature producible in the laboratory. But some of the miss- 

 ing lines have been found in the spectra of the hottest stars, stars far 

 hotter than our sun. At the same time many of the lines obtained by 

 terrestrial means are lacking in the spectra of these stars. We have 

 ample experimental evidence that many complex substances dissociate, 

 as we call it, into less complex substances within the temperature 

 range readily controlled in the laboratory. The inference is right at 

 hand that at extreme, at stellar, temperatures our elements themselves 

 are dissociated into simpler substances. To these substances, our ele- 

 ments, in this other condition, have been given their customary names, 

 but with the prefix proto. Thanks to the introduction of Rowland's 

 diffraction gratings for the study of these spectra, we have observa- 

 tions indicating the existence of proto hydrogen, proto calcium, proto 

 magnesium, proto iron and so on through a list of a dozen or more 

 1 proto ' elements. 3 



Continuation of the work upon which Crookes was engaged resulted 

 in the discovery of the X-rays by Eontgen in 1895. This date may 

 be said to mark a new era in many of our conceptions regarding the 

 universe about us. To J. J. Thomson, professor of physics at Cam- 

 bridge, England, we owe the greater part of our present knowledge of 

 the cathode rays. He devised most of the experiments and the in- 

 genious, but strictly logical, reasoning which justify us in supposing 

 that these cathode rays consist of swarms of minute particles, which 

 he called corpuscles (reviving an old term and an old theory of Isaac 

 Xewton's) ; particles moving with velocities approaching that of light, 

 each one carrying a charge of what we call negative electricity. He, 

 and those working with him, determined the quantity of this electrical 

 charge to be the same on each corpuscle, and to be the same as the 

 charge we have good reason to suppose is carried by any monovalent 

 ion in solution. By several methods the approximate number of these 

 particles in a given volume and the weight of the individual particle 

 were estimated. This weight appears to be about one eight-hundredth 

 of the weight generally ascribed to the hydrogen atom, the lightest of 

 all the atoms. It may be objected that there is no positive proof of 

 the existence of these corpuscles, nor do we know the weight or mass 

 of one of them. That is very true, but neither have we positive proof 

 of the existence of atoms, nor do we know the weight of one atom. 

 ^Ye can only say that the evidence makes the existence of these minute 

 individuals, atoms and corpuscles extremely plausible, and makes one 

 as plausible as the other. 



3 The methods, facts and reasonings relating to this spectroscopic evidence 

 are interestingly given in ' Inorganic Evolution ' by Sir Norman Loekyer. 



