THE SUN 273 



Next beneath the chromosphere comes the reversing 

 layer, relatively dark, of uncertain depth, and containing 

 the cooler gases which are responsible for the Frannhofer 

 lines in the solar spectrum. 



And, finally, the shell or layer that will engage our 

 attention here most, and which holds within it the key to 

 them all the photosphere. 



We see, then, from the premises, that the sun pre- 

 sents not one only but a complexity of enigmas, all of 

 which must be solved consistently ivith each other. His 

 longevity; his occasional lapses and recoveries; the in- 

 tensity of his light and heat; his density; his eruptive 

 character; his sun-spots; their periodicity; his corona; 

 its unresistingness ; his absence of oblateness; his axial 

 rotation per se; the cause of his equatorial acceleration; 

 his share in the genesis of his system ; his beginning and 

 his destiny; his dynamical relationship to the stars in 

 general ; his relationship to comets and meteors ; his path 

 in space; the source of his magnetism; his connection 

 with such terrestrial phenomena as earthquakes, elec- 

 trical storms, climatic reversals, and the like all these 

 we shall treat of in detail and prove them intimately and 

 causally interdependent. 



SOLUTION OF THE SOLAR PROBLEMS 



One of the many serious objections to the Nebular 

 Hypothesis is the fact that the residual mass, to wit, the 

 sun, does not revolve on its axis with anything like the 

 velocity demanded of it. According to Kepler's third 

 law, this velocity should be at least 200 times more rapid 

 than it is in nature. Furthermore, according to La- 

 place's idea, the entire solar body should revolve as a 

 rigid solid, notwithstanding the mobility of its component 

 materials; whereas there is noted a decided acceleration 

 of the equatorial regions, amounting to as much as ten 

 per centum over what it is in the middle latitudes. At- 

 tempts have been made by both Chamberlin and See to 

 account for this phenomenon; the former by supposing 

 that his ancestral sun may have had a different direction 



