XXIII.] FROM A CHEMICAL STANDPOINT. 177 



cule or mass, call it what we will, which produces the restricted number 

 of Iine3 the enhanced lines must be less than that of the magnesium 

 by the breaking up of which it is brought into a separate existence. 



And now comes .the chief point in relation to the periodic law. 

 Seeing that the smaller masses which produce the enhanced lines have not 

 been yet isolated, their " atomic " weights and their chemical characteristics 

 have not been determined, and so of course their places in the periodic table 

 cannot be indicated as it at present exists. 



My contention, therefore, is that some, at all events, of the ap- 

 parent discrepancies for there are discrepancies between the stellar 

 evidence and the " periodic " hypothesis arise from this cause. 



The magnesium, and I will now add calcium, which the chemist 

 studies at relatively low temperatures have atomic weights of 24 and 

 40 respectively, and the stellar evidence would be in harmony with 

 the periodic law if magnesium (24) made its appearance after sodium 

 (23), and calcium (40) after chlorine (39), and generally each substance 

 should make its appearance after all other substances of lower atomic 

 weight than itself. 



But, and again for the sake of simplicity I shall confine myself to 

 magnesium and calcium for the moment, in the stars we find lines in 

 the high temperature spectrum of magnesium and calcium appearing 

 before known lines in the spectrum of oxygen which has an atomic 

 weight of 16. 



How are these results to be reconciled 1 I suggest that the expla- 

 nation is that the substances revealed by the enhanced lines of mag- 

 nesium and calcium and noted in the hottest stars have lower atomic 

 weights (smaller masses) than the oxygen of the periodic table. 



Let us next, then, see what these atomic weights may possibly be. 

 Assuming A/2, the atomic weight of proto-magnesium would be 24/2 = 

 12 ; of proto-calcium 40/2 = 20, supposing only one depolymerisation 

 has taken place. If we assume two depolymerisations, we get 6 and 10 

 as the " atomic " weights of the simpler forms of magnesium and 

 calcium which make their appearance in the hottest stars. 



In this way we can explain the appearance of those finer forms of 

 magnesium and calcium before oxygen, with a small number of depoly- 

 merisations, and the stellar record of the order of atomic weights 

 would be the same : 



Hydrogen . . . . . . 1 



Profco-calcium .. .. .. 10 



Proto-magnesium . . . . 12 



Oxygen . . . . . . . . 16 



So much, then, for a possible reconciliation. The next point to be 

 considered is, is depolymerisation on such a small scale sufficient I 



N 



