Hi guys. I was searching about electricity lately and noticed something: Milikan determined the charge of an electron as 1.602*10^-18 coulomb(1 e=.1.602*10^-18 C). If he used the unit "coulomb" in his work, coulomb must exist in his times. 1 coulomb is defined as the charge of 6.24*10^19 electrons(1 C= 6.24*10^19). If i take the reverse of (1 C= 6.24*10^19), i get (1 e=.1.602*10^-18 C). In conclusion there was no need to do the oil drop experiment to find the charge of one electron if one coulomb was already defined in his times. Where am i wrong? Which is older, the definition of C or the oil drop experiment?