84 SCIENCE IN SHORT CHAPTERS. 



portion of the ejected atmospheric matter of the prominences 

 will be swept permanently to the rear, and its place supplied 

 by the material occupying the space into which the sun is 

 advancing. We are thus presented with a mighty machinery 

 of solar respiration ; some of this newly arriving atmospheric 

 natter must be stirred into the vortices, its quantity being 

 xactly equivalent to that of the old material expired by the 

 explosive eruptions, and left in the rear. 



Now, the new atmospheric matter which is thus encountered 

 and inspired is the recipient of the everlasting radiations 

 whose destination is the subject of Mr. Grove's inquiry ; and 

 these, when thus encountered and compressed, will of neces- 

 sity evolve more or less of the heat which, through millions of 

 millions of centuries, they have been gradually absorbing ; 

 while, on the other hand, the expired or ejected matter of the 

 gaseous eruptions will, like the artificially compressed air above 

 referred to, have lost all the heat which during its solar exist- 

 ence it had by compression, dissociation, and recombination 

 contributed to the solar radiations. Therefore, when again 

 fully expanded, it will be cooler than the general medium from 

 which it was originally inspired by the advancing sun. 



The daily supply of fresh atmospheric fuel will be a cylinder 

 of ether of the same diameter as the sun, and 450,000 miles 

 in length ! I have calculated the weight of this cylinder of 

 ether on the assumption (which of course is purely arbitrary) 

 that the density of the interstellar medium is one ten-thou- 

 sandth part of that of our atmosphere. It amounts to 

 14,313,915,000,000,000,000 tons, affording a supply of 165 

 millions of millions of tons per second ; or, if we assume the 

 interstellar medium to have a density of only one millionth of 

 that of our atmosphere, the supply would be rather more than 

 one and a half millions of millions of tons per second. The 

 proportion of this which is effective in the manner above 

 stated is that which becomes stirred into the lower regions of 

 the sun in exchange for the ejected matter of the prominences. 



I will not here dwell upon the bombardment hypothesis, 

 beyond observing that my explanation of solar phenomena sup- 

 plies a continuous bombardment of the above stated magnitude 

 without adding anything to the magnitude of the sun. 



So far, then, I answer Mr. Grove's question, by showing that 

 the heat radiated into space by each of the solid orbs that people 

 its profoundities, is received by the universal atmospheric 

 medium ; is gathered again by the breathing of wandering 



