_But I call that Body more grave absolutely than this, if that weigh more than this, without any respect had to the Masses._
And thus a great piece of Wood is said to weigh more than a little lump of Lead, though the Lead be _in specie_ more heavy than the Wood. And the same is to be understood of the less grave _in specie_, and the less grave absolutely.
These Termes defined, I take from the Mechanicks two Principles: the first is, that
