xvi Proceedings of the Royal Society of Victoria. 



the two, so that, if he can substantiate his claim, we shall 

 have three elements — one the true cobalt, another the true 

 nickel, and one new one. The true cobalt and the true 

 nickel will not have the atomic weights we are accustomed 

 to associate with those names, and an old mystery may thus 

 be cleared up. But further, the new element will want a 

 place in the systematic classification, and it seems to me 

 possible — just ])0ssible — that our friend the 99 or 100 gap 

 may now be filled. Chemists await with keen anxiety the 

 arrival of journals with Professor Kriiss' complete accounts 

 of his work ; till then, we must be cautious, even to the 

 point of incredulity^ 



But, after all, shall we have arrived at the end of 

 things when all the elements are discovered and their 

 atomic weights and all their phj^sical and chemical properties 

 have been accurately determined ? Is there nothing behind 

 the elements ? What is the real nature of a so-called 

 elementary atom, and what are we to understand by the 

 phrase "atomic weights"? 



The wonderful and laborious researches of Crookes, Kmss, 

 Nilson,and of others, on the so-called "rare earths" have led 

 the first of these chemists (who is remarkable alike for skill 

 in experiment, and the strength of his power of generalisa- 

 tion) to put forward a theory that each resting point in the 

 periodic classification marks the existence not of one 

 element with an absolutely fixed atomic weight, but of a 

 cluster of ^leto-elements as he calls them, substances barely 

 distinguishable from one another by chemical means but 

 capable of being differentiated by the spectroscope and of 

 being separated by methods such as fractional precipitation, 

 and that the atomic weight of an element is really only the 

 mean of the atomic weights of the meta-elements which 

 compose it — numbers varying from the mean within narrow 

 limits. His theory further takes us into a most suggestive 

 speculation concerning the genesis of the elements and their 

 met;velements from one primordial form of matter, to which 

 he has given the name o'i. protyle. 



