A NEW THEORY OF THE SUN. 235 



owing to such differences in the quality of the fuel supplied that the 

 observed variations of the solar heat may arise ? and may it not be 

 in consequence of such changes in the thermal condition of the photo- 

 sphere that the extraordinary convulsions revealed to us as sun-spots 

 occur ? 



The views here advocated could not be thought acceptable unless 

 they furnished at any rate a consistent explanation of the still some- 

 what mysterious phenomena of the zodiacal light and of comets. 

 Regarding the former, we should be able to revert to Mairan's views, 

 the objection by Laplace being met by a continuous outward flow 

 from the solar equator. Luminosity would be attributable to particles 

 of dust emitting light reflected from the sun, or to phosphorescence. 

 But there is another cause for luminosity of these particles, which may 

 deserve serious consideration. Each particle would be electrified by 

 gaseous friction in its acceleration, and its electric tension would be 

 vastly increased in its forcible removal, in the same way as the fine 

 dust of the desert has been observed by Dr. Werner Siemens to be in 

 a state of high electrification on the apex of the Cheops Pyramid. 

 Could not the zodiacal light also be attributed to slow electric dis- 

 charge backward from the dust toward the sun ? and would not the 

 same cause account for a great difference of potential between the sun 

 and earth, which latter may be supposed to be washed by the solar 

 radial current ? May not the presence of the radial solar current also 

 furnish us with an explanation of the fact that hydrogen, while 

 abounding apparently in space, is practically absent in our atmosphere, 

 where aqueous vapor and carbonic acid, which would come to us 

 directly from the sun, take its place ? An action analogous to this, 

 though on a much smaller scale, may be set up also by terrestrial rota- 

 tion, giving rise to an electrical discharge from the outgoing equato- 

 rial stream to the polar regions, where the atmosphere to be pierced by 

 the return flood is of least resistance. Thus the phenomenon of the 

 aurora borealis or northern lights would find an easy explanation. 



The effect of this continuous outpour of solar materials could not 

 be without very important influences as regards the geological con- 

 ditions of our earth. Geologists have long acknowledged the diffi- 

 culty of accounting for the amount of carbonic acid that must have 

 been in our atmosphere, at one time or another, in order to form with 

 lime those enormous beds of dolomite and limestone, of which the 

 crust of our earth is in great measure composed. It has been calcu- 

 lated that, if this carbonic acid had been at one and the same time in 

 our atmosphere, it would have caused an elastic pressure fifty times 

 that of our present atmosphere ; and, if we add the carbonic acid that 

 must have been absorbed in vegetation in order to form our coal-beds, 

 we should probably have to double that pressure. Animal life, of 

 which we find abundant traces in these "measures," could not have 

 existed under such conditions, and we are almost forced to the conclu- 



