252 THE POPULAR SCIENCE MONTHLY 



ATTEMPTS TO EXPLAIN GRAVITATION 



Br WILSON C. MORRIS 



STATE NORMAL SCHOOL, WARRENSBDRG, MO. 



TO the casual observer the heavenly bodies may seem isolated; but 

 careful study will show how closely connected they are. Not only 

 are they much alike in composition, but across the vast gulfs separating 

 them they hold constant intercourse. Before the time of Newton the 

 only influence known to pass from one heavenly body to another was 

 what we now call radiant energy. To this Newton added a second influ- 

 ence, the force of gravitation. To this list we may also add a third, 

 electrical attraction. The one with which this paper deals is gravita- 

 tional attraction. 



To the student who has at least an elementary knowledge of physics 

 or astronomy gravitational attraction is one of the best known prop- 

 erties of matter; and it can just as truly be said that it is one of the 

 least understood properties of matter, not only by elementary students 

 but by mature physicists and astronomers. So often has the problem 

 of gravitation evaded solution that some in despair have doubted the 

 ability of the human intellect to grapple successfully with it. This feel- 

 ing may have been strengthened by Newton's references to himself. 



At present we can't tell how one body attracts another; and the 

 science-producing value of the efforts made to explain the mechanism 

 of attraction is not to be judged by the prospects afforded of ultimately 

 obtaining a solution but by the stimulus afforded in furthering 

 thorough investigation. What we want is a hypothesis that will con- 

 form to well-known phenomena and that will stimulate further investi- 

 gation. It is needless to say that final solution finds no place in our 

 attempt. 



Most of the conjectures concerning gravitation have not reached 

 the dignity of a hypothesis. Some of them seem even too wild for a 

 romance. I think it is Schuster who has referred to his conjectures 

 regarding gravitation as a- holiday-dream. I like this word in this 

 connection. However since they are the best we have let us make the 

 most of them or supplant them with better ones. 



Before reciting some of the attempts to explain gravitation it might 

 be well to refer briefly to its discovery, magnitude, peculiarities, etc. 

 Kepler had stated in his first law that the earth revolves in an elliptical 

 orbit with the sun at one focus. With this knowledge at hand, by 

 strictly dynamical reasoning Newton showed that bodies attracted 



