Mathematicians Of The Day

18th September

On this day in 1846, Le Verrier wrote to Johann Galle at the Berlin Observatory asking him to look for a planet at the position he predicted. Galle located Neptune five days later.

On this day in 2013 Google released a Foucault doodle.

Click on for a poster.

Quotation of the day

From Leonhard Euler
If a nonnegative quantity was so small that it is smaller than any given one, then it certainly could not be anything but zero. To those who ask what the infinitely small quantity in mathematics is, we answer that it is actually zero. Hence there are not so many mysteries hidden in this concept as they are usually believed to be. These supposed mysteries have rendered the calculus of the infinitely small quite suspect to many people. Those doubts that remain we shall thoroughly remove in the following pages, where we shall explain this calculus.