THE HIGHEST AIM OF THE PHYSICIST 671 



tion is proportional to the quantity of matter, which is the same as 

 saying that the attraction of one body by another is not affected by the 

 presence of a third, the feeble proof that we give by weighing bodies in 

 a balance in different positions with respect to each cannot be accepted 

 on a larger scale. When we can tear the sun into two portions and prove 

 that either of the two halves attracts half as much as the whole, then 

 we shall have a proof worth mentioning. 



Then as to the relation of gravitation and time what can we say? 

 Can we for a moment suppose that two bodies moving through space 

 with great velocities have their gravitation unaltered? I think not. 

 Neither can we accept Laplace's proof that the force of gravitation acts 

 instantaneously through space, for we can readily imagine some com- 

 pensating features unthought of by Laplace. 



How little we know then of this law which has been under observa- 

 tion for two hundred years! 



Then as to matter itself how have our views changed and how are 

 they constantly changing. The round hard atom of Newton which 

 God alone could break into pieces has become a molecule composed of 

 many atoms, and each of these smaller atoms has become so elastic that 

 after vibrating 100,000 times its amplitude of vibration is scarcely 

 diminished. It has become so complicated that it can vibrate with as 

 many thousand notes. We cover the atom with patches of electricity 

 here and there and make of it a system compared with which the plane- 

 tary system, nay the universe itself, is simplicity. Nay more: some of 

 us even claim the power, which Newton attributed to God alone, of 

 breaking the atom into smaller pieces whose size is left to the imagina- 

 tion. Where, then, is that person who ignorantly sneers at the study 

 of matter as a material and gross study? Where, again, is that man with 

 gifts so God-like and mind so elevated that he can attack and solve its 

 problem? 



To all matter we attribute two properties, gravitation and inertia. 

 Without these two matter cannot exist. The greatest of the natural 

 laws states that the power of gravitational attraction is proportional to 

 the mass of the body. This law of Newton, almost neglected in the 

 thoughts of physicists, undoubtedly has vast import of the very deepest 

 meaning. Shall it mean that all matter is finally constructed of uniform 

 and similar primordial atoms or can we find some other explanation? 



That the molecules of matter are not round, we know from the facts 

 of crystallography and the action of matter in rotating the plane of 

 polarization of light. 



