Charles Augustin de
Coulomb (1736 – 1806)
Coulomb, a French
physicist, began his
career as a military
engineer in the West
Indies In 1776, he
returned to Paris and
retired to a small estate
to do his scientific
research He invented a
torsion 
balance 
to
measure the quantity of
a force and used it for
determination of forces
of electric attraction or
repulsion between small
charged spheres He
thus arrived in 1785 at
the inverse square law
relation, now known as
Coulomb’s law