LVT BUREAU OF AMERICAN ETHNOLOGY 



The second quantity is space; its essential is extension, 

 but many exteiisions give rise to relative position, and the 

 positions can be measured. Hence extension and jxisition 

 constitute space, and space is a quantity that can be measured. 



Speed is the essential of motion, but the same particle in 

 motion traverses a path. Motion, thei'efore, is speed and path, 

 and can be measured in terms of space. Speed and path con- 

 stitute motion. Therefore time is a quantity. 



The essential of time is persistence, but the relation of time 

 is change; a portion of time from one change to another may 

 be measured. Thus persistence and change constitute time, 

 and time is a quantity. 



The essential of judgment is consciousness of self. Its rela- 

 tion to others is inference aborit others. When consciousness 

 is aroused by another, and by inference a judgment is pro- 

 duced of that other, it can be measured. If I judge that there 

 are eight others, I can measure that judgment by counting the 

 others. The judgment is measured by comparing it with the 

 fact. If I judge of a distance, I can measure this judgment 

 by measuring the distance, and the judgment is measured by 

 the fact. If I judge of the rate of a motion or the distance 

 which a b()d}' moves, I can measure this rate or distance and 

 by comparing the judgment with the fact I obtain a measure- 

 ment of the judgment. If I judge of the lapse of time and 

 then measure this lapse, the judgment may be measured by 

 the fact. 



As the essentials are developed into mathematical properties 

 called quantities, so again the quantities are developed by incor- 

 poration into classific properties or, simply, properties. In this 

 development luimber becomes class, unity becomes kind, and 

 plurality becomes mass. The kind is constant as long as the 

 body is constant, but the mass is variable. 



When space becomes form, then extension becomes indi- 

 viduality and mass becomes structure. The individuality is 

 constant as long as the body is constant, but the structure is 

 variable. 



When motion becomes energy, then speed becomes inertia 

 and path becomes velocity. Inertia is constant, but velocity 

 is ^•ariable. 



