404 Mr. E. H. Cook on the Regenerative 



tion of the C0 2 and H 2 does not occur, we have at the 

 bounding surfaces at any rate, and, as is admitted, sometimes 

 far down into this inner atmosphere, a large mass of water- 

 vapour and carbon dioxide in contact with metallic vapours. 

 Here, then, surely combination will occur between the metals 

 and the oxygen of water, setting free the hydrogen. Large 

 quantities of the oxides of sodium, potassium, calcium, mag- 

 nesium, which it is impossible to decompose at any terrestrial 

 temperature, would thus be produced. Most of the oxygen 

 would thus be retained in the sun itself; and thus the consti- 

 tution of the gases projected into space would be very differ- 

 ent from that supposed by Dr. Siemens. The comparison of the 

 solar spectrum with the spectra of these metals seems to con- 

 clusively prove that the bodies existing in the sun are the 

 elements themselves and not any compound of them. This 

 being so, it shows that the temperature is higher than that of 

 the dissociation of these oxides ; but if higher than this, surely 

 it must be very much higher than that at which such bodies 

 as carbon dioxide and water can exist. 



Referring to the metallic vapours revealed to us by the 

 spectroscope, Dr. Siemens says : — " These form a lower and 

 denser solar atmosphere, not participating in the fan-like 

 action which is supposed to affect the light outer atmosphere 

 only, in which hydrogen is the principal factor.*' This 

 assumption is difficult of acceptance, inasmuch as any force 

 which affects one body will also affect another, even though 

 they differ in density. It is simply a question of degree: and 

 if, owing to centrifugal force, hydrogen is projected x miles 

 into space, then sodium-vapour, which is 23 times as heavy, 



Of 



will be projected ^ miles. Again, we are told carbon dioxide 



and water are formed and projected into space, but in conse- 

 quence of the greater density of the materials composing the 

 inner atmosphere they do not suffer propulsion. But here 

 we are in error. A large number of the metallic vapours have 

 densities which are very little greater than the density of C0 2 ; 

 and some are absolutely less. Thus the specific gravity of 

 carbon dioxide compared with hydrogen is 22, that of lithium- 

 vapour is only 7, of beryllium 9*2, of sodium 23, magne- 

 sium 24, and aluminium 27. All these have been proved to 

 exist in the sun. Since they are specifically lighter than the 

 supposed products of combustion, and are also exposed to the 

 same heat, and therefore expanded just as much, it is unreason- 

 able to suppose they are not affected in the same way by the 

 action of the centrifugal force. If, however, we imagine these 

 metals to combine with oxygen, we are in no way better off ; 

 for here again the products are very little heavier than the 



