COAL AS A RESERVOIR OF POWER. 
163 
constantly going forward in the sun, and producing those radia- 
tions which are poured forth in volumes, far beyond the re- 
quirements of all the planets of our system. Although there is 
probably some circle of action analogous to that which exists 
upon this earth, maintaining the permanency of the vegetable 
and animal world, still there must be a waste of energy, 
which must be re-supplied to the sun. 
May it not be, that Sir Isaac Newton’s idea, — that the comets 
traversing space gather up the waste heat of the solar system, 
and eventually, falling into the sun, restore its power, — is nearer 
the truth than the more modern hypothesis, that meteorites are 
incessantly raining an iron shower upon the solar surface, and 
by their mechanical impact reproducing the energy as con- 
stantly as it is expended. 
