## Mathematicians Of The Day

### 21st March

On this day in 1684, Giovanni Cassini discovered two moons of Saturn: Tethys and Dione. He had previously discovered two other satellites of Saturn: Iapetus (in 1671) and Rhea (in 1672). Christiaan Huygens was the first to discover a moon of Saturn, when he viewed Titan (the largest and easiest to see) in 1655.

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##### Born:

- 1768: Joseph Fourier Ⓟ
- 1831: Dorothea Beale Ⓟ
- 1855: Louis Raffy
- 1863: James Watt
- 1884: George Birkhoff Ⓟ
- 1920: John Hammersley Ⓟ

##### Died:

- 1762: Nicolas-Louis de Lacaille Ⓟ
- 1822: Charles Tinseau
- 1933: Enrico D'Ovidio Ⓟ
- 1934: Thomas Muir Ⓟ
- 1952: John Alison
- 1960: Sheila Scott Macintyre Ⓟ
- 2009: Thierry Aubin Ⓟ
- 2010: Fritz Grunewald Ⓟ
- 2020: Volodymyr Petryshyn Ⓟ

#### Quotation of the day

##### From Joseph Fourier

The profound study of nature is the most fertile source of mathematical discoveries.