THE SCIENTIFIC METHOD 133 



may be expressed in mechanical ideas and that the 

 fundamental units of measurement are mass, length, 

 and time. These are continuous functions and con- 

 sequently indefinitely divisible. 



While matter, as measured by mass and extent, is 

 indefinitely divisible, it is convenient to adopt as a 

 scientific unit of mass a quantity so small that it is 

 inferior to our powers of observation and so must be 

 treated mathematically only in aggregates. As this is 

 a general definition, the name protion has been given 

 to this unit in order to avoid confusion with the chem- 

 ical atom and the electron. At the present time the 

 protion is the electron. 



The general laws governing actions are the laws of 

 continuity and conservation and the law of cause and 

 effect. These are generalizations from experience and 

 cannot be extended beyond possible experience without 

 great precaution. 



Energy is defined as the power of doing work and is 

 held to be an attribute of matter. True or observa- 

 tional energy is always associated with matter and is 

 divided, for convenience, into potential and kinetic 

 energy. 



A third and hypothetical kind of energy is assumed 

 in order to extend quantitatively the laws of continuity 

 and conservation, and of cause and effect, to the 

 apparently well-founded interchange of energy of 

 two bodies situated in a vacuum. This energy is named 



