Gottfried Wilhelm (von) Leibniz (; or ; ; July 1, 1646 – November 14, 1716) was a German polymath and philosopher who occupies a prominent place in the history of mathematics and the history of philosophy. Scholars including Bertrand Russell believe Leibniz developed calculus independently of Isaac Newton, and Leibniz's notation has been widely used ever since it was published. It was only in the 20th century that his Law of Continuity and Transcendental Law of Homogeneity found mathematical implementation (by means of non-standard analysis). He became one of the most prolific inventors in the field of mechanical calculators. While working on adding automatic multiplication and division to Pascal's calculator, he was the first to describe a pinwheel calculator in 1685 and invented the Leibniz wheel, used in the arithmometer, the first mass-produced mechanical calculator. He also refined the binary number system, which is the foundation of virtually all digital computers.