74 UNIVERSITY OF MISSOURI BULLETIN 



Recently there has arisen a subject called Relativity, 

 which takes for one of its axioms or fundamental assumptions 

 the fact that the observed velocity of light appears to be 

 independent of all motion. As a result it is shown that all 

 our units for the measurements of time, length, and mass will 

 depend upon absolute motion. In other words, a meter 

 stick will have a slightly different length when in motion, 

 than when at rest. The mass of a moving body does not 

 remain constant if the speed changes. Increase the speed and 

 the mass increases. Or a clock or any timekeeper will run 

 at a different rate when in motion than when stationary. But 

 these changes which arise through motion appear to be ex- 

 tremely minute, and at all ordinary speeds defy detection. 

 Thus arises what may be called non-Newtonian mechanics, 

 a subject becoming as interesting to physicists as non- 

 Euclidean geometry is to mathematicians. 



When we turn to the relations between our fundamental 

 concept of matter and that of electricity, we find that a great 

 deal of experimental work has been done and that consider- 

 able light has been thrown on this fundamental problem. It 

 was long ago pointed out that the electrical discharge through 

 the vacuum tube where matter exists in probably its simplest 

 state would afford us favorable conditions for observation. 

 Results have exceeded even the most sanguine expectations. 

 Many new phenomena have been discovered, for example, 

 kathode rays and X-rays. The discovery of this last created 

 an increased interest and the discovery of radium was an 

 almost immediate result. But the most important thing 

 found in the vacuum tube has been the electron. The next 

 lecturer in this course will doubtless tell us more about this, 

 and that the electron with its charge of electricity seems to 

 be the fundamental unit of matter, a theory we now call the 

 electrical theory of matter. Since the electron is a charge 

 of electricity, matter is then built up from electricity. If this 



