110 Mr. H. M. Vernon on the 



obtained, and when in this condition subjected to the influence 

 of the induction-discharge, phosphoresce, most of them, it is 

 true, for but a very short time ; but with the phosphoroscope 

 contrived by Crookes most of them would phosphoresce long 

 enough to allow of their being satisfactorily examined by 

 means of a spectroscope. Bodies treated in this way are said 

 to undergo the radiant-matter test. 



When these nine earths, fractionated from yttria, were sealed 

 up in tubes with a suitable degree of exhaustion, and their 

 phosphorescent spectra obtained in this way, it was found 

 that the spectra of all of them differed to a certain extent. 

 The further the earths were removed from each other in 

 respect of basicity, the more were their phosphorescent 

 spectra found to differ, those of the extreme fractions showing 

 considerable differences. 



The differences of phosphorescent spectra appear to be, at 

 least in the case of the yttria earths, the only grounds on 

 which Crookes founds his supposition of the fractionation of 

 this so-called single earth into these nine others. On the 

 strength of the fact of these bodies having slightly different 

 phosphorescent spectra, both when examined alone and, as 

 will be mentioned hereafter, when mixed with other earths, 

 he considers that the earth has been split up into several 

 others, each of which is to be considered the oxide of a 

 different element or meta-element, 



The question comes, Do these fractions of the original 

 earth differ in chemical properties as well as in phosphorescent 

 spectra ? The answer is, No. The only chemical property 

 in which they appear to differ is that of a slight difference of 

 basicity among themselves. Crookes has not shown that 

 they possess any other chemical properties whatever which 

 may serve to differentiate them from each other ; indeed, it 

 appears that he has not yet tried to prepare their salts and 

 show whether or not they are identical. 



Again, the question comes, If these bodies do not differ in 

 chemical properties, do they not differ in physical proper- 

 ties other than that of possessing different phosphorescent 

 spectra? Again the answer is, No. Have we not been 

 taught, as one of the fundamental principles of our science, 

 that every different form of matter possesses a spectrum 

 which belongs to it and to it alone ? If, then, these so-called 

 meta- elements are different forms of matter, should not they 

 also be expected to come within the precincts of this universal 

 rule? Surely yes. On examination, however, is this the 

 case? In a lecture before the Royal Institution (Chemical 

 News, 1887, p. 87), Crookes brings before the assembly the 



