F. W. Very — A Cosmic Cycle. 47 



Art. Y. — A Cosmic Cycle ; by Frank W. Yery. 



Fokms suggesting the existence of tremendous explosive 

 agencies in nature are familiar to every student of astronomy. 

 Ranyard, in his completion of Proctor's " Old and New 

 Astronomy," has called attention to numerous examples.* In 

 thinking over the probable meaning of these forms and casting 

 about for a sufficient cause for such powerful exhibitions of 

 force, I have been led to consider an explanation which 

 involves an extension of the doctrine of the conservation of 

 energy. Before proposing it I must recall a few facts and 

 commonly admitted hypotheses. 



Solar Phenomena. 



A few consequences of the contraction theory of the origin 

 of the sun's heat may be briefly summarized : 



The transformation of potential energy of position into 

 molecular and atomic kinetic energy produces increasing tem- 

 perature of the solar mass. A scattered meteor-swarm, by 

 myriads of internal impacts between component meteors, is 

 gradually changed from a collection of massive solid frag- 

 ments into a liquid nucleus surrounded by a diminishing 

 meteoric swarmf with an interpenetrating gaseous atmosphere ; 

 and as the liquid nucleus increases, its temperature and pres- 

 sure rise until the center also becomes gaseous, and the critical 

 stage is passed, after which no amount of pressure can liquefy 

 the mass. Further condensation, giving increase of pressure, 

 simply raises the temperature. But it is obvious that 'there 

 must be some limit to the process, and the accepted hypothesis 

 is that after a certain stage of condensation has been passed, 

 radiation increases with temperature at a more rapid rate than 

 temperature as a result of condensation. 



This brings us at once to the problem of the mode of dis- 

 persal of the thermal energy produced throughout the mass. 

 Since this dispersal can only be effected at the outer surface, 

 there must be a transferring of thermal energy from center to 

 surface at a sufficiently rapid rate to supply the surface output. 

 Conduction proceeds too slowly for this purpose. Convection 

 is competent to perform such a function up to a certain point 

 and is also evidenced by the phenomena of the solar spots ; but 

 since viscosity, which impedes convection, increases with tem- 

 perature, it may be doubted whether convection, in turn, is 



*See especially Arts. 1421, 1424, and the end of 1445. 



\ The zodiacal light possibly represents the last remnant of such a swarm in 

 our own system. 



