THE AUTHOR'S THEORIES OUTLINED 



Here we are confronted with three controlling con- 

 ditions, namely: (1) Plasticity of the solar shell, (2) 

 Gradually increasing temperatures and pressures (ex- 

 plosive) as we descend below the surface, and (3) Great 

 diversity between our materials in the two decisive re- 

 spects of volatility and specific gravity (atomic weight). 

 We thus have the elements of a sort of obstacle race, in 

 which the test of merit consists in ascertaining which of 

 the entrant materials can penetrate farthest before 

 undergoing re-volatilization and re-expulsion. Obvi- 

 ously, that particular element or compound that pos- 

 sesses at once the highest specific gravity and the strong- 

 est refractoriness (qualities usually associated) may 

 sink clear through the shell into the central retort, while 

 the rest will penetrate in like manner to their several 

 appropriate levels. In fine, the shell progresses toward 

 homogeneity and refractoriness as we descend, and here- 

 in we behold in our sun, not alone a fountain of light and 

 heat, but a natural smelter by which Nature assorts for 

 man's sake? her diversified materials. These deduc- 

 tions suggest to us the chemical secrets of meteorites 

 and the cause of the natural segregation of our ore de- 

 posits. 



Going back to our obstacle race, we note that, inas- 

 much as each substance has its separate characteristics, 

 its eruptive interval is lengthened or shortened accord- 

 ingly. The cycle of the most volatile will be so short as 

 to be in effect continuous and the resulting eruptions or 

 geysers so countless as rather to deserve the title of ebul- 

 litions. Such are the so-called "rice grains". On the 

 other hand, the longer it takes a given substance, or class 

 of substances, to round their cycle, the longer will be the 

 interval between displays, the deeper the seat of the 

 blast, and the more distinct the period and resulting 

 phenomena. Of this nature are the "sun-spots", whose 

 average period is slightly more than eleven years. 

 There are, however, many shorter cycles, though not as 

 yet clearly defined, and one, or perhaps more, long, 

 epoch-creating ones, of which we have no historical but 



