MIRACLES OF SCIENCE 



But lest the uninitiated suppose that this sugges- 

 tion is altogether anarchistic, let me hasten to add 

 that Professor Campbell does not mean to imply 

 quite what his words seem to suggest. He does not 

 for a moment suppose that there was ever a time 

 when Newton's law of gravitation was not operative; 

 he means only that there may be conditions under, 

 which its action is overcome by antagonistic forces. 



When you throw a pebble into the air, you mo- 

 mentarily annul the power of gravitation over that 

 stone. But even while the pebble is flying straight 

 upward, in seeming defiance of gravity, it is being 

 acted on just as definitely and just as vigorously by; 

 the gravitation pull as before; only the force of pro- 

 pulsion given by your arm-thrust masks and for the 

 moment overbalances that resistant downward pull. 



LIGHT PRESSURE AS A COSMIC FORCE 



And so it is, according to Professor Campbell's 

 suggested hypothesis, with the materials that make 

 up the nebulous mass, which, according to the best 

 modern notions of the astronomer, constitutes the 

 first stage of star-development. The reader who has 

 not viewed a nebula through a telescope has doubt- 

 less seen reproductions of photographs of nebulae, or 

 at any rate of a comet, the tail of which is a nebula 

 in miniature. It will be recalled, therefore, that a 

 nebula seems to be made up of very fine particles of 

 matter. Professor Campbell suggests that these 

 particles of matter are so subject to "radiation pres- 

 sure" that their tendency to gravitation toward other 

 bodies is for the moment overcome. 



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