264 FROM NEBULA TO NEBULA 



of the earth in the same ratio as the temperature of the sun is 

 to that at which the chemical reactions are proceeding on the 

 earth. As these gases penetrate farther into the sun, temperature 

 and pressure are still more and more increased, and there will 

 result products more and more abounding in energy and con- 

 centration. We may, therefore, imagine the interior of the sun 

 charged with compounds which, brought to the surface of the 

 sun, would dissociate under an enormous evolution of heat and 

 an enormous increase of volume. These compounds have to be 

 regarded as the most powerful blasting agents, by comparison 

 with which dynamite and gun-cotton would appear like toys. In 

 confirmation of this view, we observe that gases when penetrating 

 into the photosphere clouds are able to eject prominences at a 

 stupendous velocity, attaining several hundred kilometres per 

 second. This velocity surpasses that of the swiftest rifle-bullet 

 about a thousandfold. We may hence ascribe to the explosives 

 which are confined in the interior of the sun energies which must 

 be a million times greater than the energy of our blasting agents. 

 (For the energy increases with the square of the velocity.) And 

 yet these solar blasting agents have already given up a large part 

 of their energy during their passage from the sun's interior. It 

 thus becomes conceivable that the solar energy instead of hold- 

 ing out for 4000 years, as it would if it depended upon the com- 

 bustion of a solar sphere made out of carbon will last for some- 

 thing like four thousand million years. Perhaps we may further 

 extend this period to several billions. 



As his final and main thesis, the learned savant 

 undertakes to explain how life-germs are disseminated 

 through the universe. First, he disposes of the argu- 

 ment in behalf of spontaneous generation by citing its 

 want of ocular proof and absence of physical demon- 

 stration. He then reminds us of Schwarzschild's deduc- 

 tion, that particles approximating .00016 mm. in diameter 

 are the most responsive to radiation pressure, and seeks 

 to extend this category to include plant and animal spores 

 and germs. These, he says, being borne away, literally, 

 on the wings of light find lodgment on distant worlds, and 

 originate new chains of evolution more or less resem- 

 bling life terrestrial. 



The theories above outlined, circumscribed, strained, 

 and mutually contradictory as they may appear, repre- 



