CHARTING THE UNIVERSE 



Notwithstanding the interrogative form in which 

 this explanation is put forward, we are perhaps fully 

 justified in assuming that Professor Campbell's ques- 

 tion marks are only the shield I had almost said 

 subterfuge with which an ultra-scientific mind often 

 tends to protect itself against the charge of hasty 

 generalizing. In point of fact, the explanation sug- 

 gested in his questions seems not only an altogether 

 valid interpretation of observed phenomena, but con- 

 stitutes perhaps the only plausible explanation that 

 could be suggested consistently with our present 

 knowledge. 



Yet to any reader who has not kept closely in 

 touch with recent advances in physical science, the 

 explanation must seem altogether startling. To sug- 

 gest that there are forms* of matter not subject to 

 Newton's law of gravitation would have seemed to 

 the physicist of even a dozen years ago a most hereti- 

 cal and unjustifiable assault upon the most funda- 

 mental of physical laws. Ever since Newton pro- 

 pounded his thesis that every particle of matter in 

 the universe attracts every other particle with a force 

 inversely as the square of distance between the 

 particles and directly as the product of their masses, 

 this "law," which seemed to explain all the motions 

 of the planetary bodies and the revolutions of double 

 stars no less than the fall of bodies at the earth's sur- 

 face, has been the very corner-stone of physical 

 science. 



(Yet Professor Campbell suggests that there is a 

 stage of stellar development at which matter seems 

 not to be subject to this law. 



49 



