THE ORIGIN OF SOLAR HEAT 



translatory motion in a straight line that it may have, 

 would, according to the laws of Inertia, require no 

 expenditure of energy or maintaining force. The 

 planets and their satellites, on the contrary, are con- 

 tinually deflected from their normal right line motion 

 by the force of 'gravitation, or the impact of the 

 ethereal atoms, which, in the instance of this earth, 

 is a force sufficient to deflect the mass of the earth 

 from a straight line into the curve of its orbit. The 

 equivalent amount of energy expended on the sun, 

 though divided proportionally between the planets 

 and the sun in the ratio of their respective masses, 

 would manifest itself in the sun as heat only, since the 

 common centre of gravity of the sun and the planets 

 is within the body of the sun itself; the latter 

 having, so far as known, no orbital motion. It is 

 certain that a large part of the Sun the photosphere 

 is in a highly heated gaseous state, which the rain 

 of atoms constantly falling on, or other cause of 

 gravitation, must tend to drive in towards the sun's 

 centre. This condensation of ponderable matter upon 

 itself must increase the temperature still higher, pro- 

 ducing or maintaining thereby that dissociation of the 

 elementary atoms that manifests itself by their incan- 

 descent light, as well as by the dark Frauenhofer 

 lines in the solar spectrum. The Ether finally 

 receives back from the glowing sun upon its isotro- 



197 



