hereafter under the name of…mass…is known by the weight…for it is
Nel 1680, Newton espose il principio d'equivalenza in termini di
forze e masse. Nel paragrafo di apertura dei "Philosophiae Naturalis
Principia Mathematica" dove scriveva: " This quantity that I mean
hereafter under the name of…mass…is known by the weight…for it is
proportional to the weight as I have found by experiments on pendulums,
very accurately made…".