Isaac Newton · every age

What was Isaac Newton doing at 64?

Invented calculus and gravity theory in a plague year at 23

1. c. 1707

   Introduced sampling a pound of coins at the trial of the pyx

   It cut the permitted error in the coinage.

   Source: en.wikipedia.org

Portrait: Portrait: Godfrey Kneller (1689), public domain, via Wikimedia Commons · source