section_path: Pre-Newtonian concepts/Mass as distinct from weight
section_name: Mass as distinct from weight
paragraph_text: Mass as distinct from weight
  
  According to K. M. Browne: "Kepler formed a concept of mass ('amount of matter' (copia materiae)), but called it 'weight' as did everyone at that time." Finally, in 1686, Newton gave this distinct concept its own name. In the first paragraph of Principia, Newton defined quantity of matter as “density and bulk conjunctly”, and mass as quantity of matter.
  
  The quantity of matter is the measure of the same, arising from its density and bulk conjunctly.... It is this quantity that I mean hereafter everywhere under the name of body or mass. And the same is known by the weight of each body; for it is proportional to the weight.