## 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.

See THIS LINK.

On this day in 2013 Google released a Foucault doodle.

See THIS LINK.

On this day in 2013 Google released a Foucault doodle.

Click on Ⓟ for a poster.

##### Born:

- 1752: Adrien-Marie Legendre Ⓟ
- 1819: Léon Foucault Ⓟ
- 1863: William Metzler Ⓟ
- 1908: Victor Amazaspovich Ambartsumian Ⓟ
- 1909: Johannes Haantjes Ⓟ

##### Died:

- 1783: Leonhard Euler Ⓟ
- 1891: William Ferrel Ⓟ
- 1896: Hippolyte Fizeau Ⓟ
- 1969: Joseph Pierce Ⓟ
- 1977: Paul Bernays Ⓟ
- 2002: Siobhán Vernon Ⓟ

#### 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.