

xxviii.] NECESSITY FOR DISSOCIATION. 423 



by successive halving, then the volume occupied will be 1024 

 times greater, and we shall have 



Volume in 



Temperature. Pressure. cubic miles. 



50,000 C 760mm. . . . 9,011 



50,000 .... 190 ... 36,044 



In these higher figures we certainly do approach the scale 

 on which we know solar phenomena to take place; the tre- 

 mendous rending of the photosphere, upward velocities of 250 

 miles a second, and even higher horizontal velocities according 

 to Peters, are much more in harmony with the figures in the 

 second table than the first. 



The. question really is how does a mass of hydrogen, or ot 

 what we call as a " short title " hydrogen, ascending at the rate 

 of 250 miles a second get its initial velocity ? 



In many theories of the solar constitution we have the 

 simple explanation that it has been squirted out of solar 

 volcanoes. But it is I think evident that such a view scarcely 

 merits discussion. Where are the volcanoes, and how can they 

 exist in a mass of gas ? 



On this point Professor Young writes as follows : 1 



" When we inquire what forces impart such a velocity, the subject 

 becomes difficult. If we could admit that the surface of the sun is 

 solid, or even liquid, as Zollner thinks, then it would be easy to 

 understand the phenomena as eruptions, analogous to those of 

 volcanoes on the earth, though on the solar scale. But it is next 

 to certain that the sun is mainly gaseous, and that its luminous 

 surface or photosphere is a sheet of incandescent clouds, like those 

 of the earth, except that water droplets are replaced by droplets of 

 the metals ; and it is difficult to see how such a shell could exert 

 sufficient confining power upon the imprisoned gases to explain such 

 tremendous velocity in the ejected matter." 



1 The Sun, p. 210. 



