## Mathematicians Of The Day

### 17th December

On this day in 1610 Father Christoph Clavius SJ, the senior mathematician at the Collegio Romano wrote to inform Galileo that he and other Jesuits at the college had seen the four moons of Jupiter. Only two months earlier he had said that if Galileo saw "planets" around Jupiter in his glass, then he must have put them there.

On this day in 2012 Google released a Chatelet doodle.

On this day in 2012 Google released a Chatelet doodle.

Click on Ⓟ for a poster.

##### Born:

- 1706: Émilie du Châtelet Ⓟ
- 1835: Felice Casorati Ⓟ
- 1842: Sophus Lie Ⓟ
- 1863: Henri Padé Ⓟ
- 1884: Heinrich Scholz Ⓟ
- 1893: Petre Sergescu Ⓟ
- 1894: Hendrik Kramers Ⓟ
- 1900: Mary Cartwright Ⓟ
- 1938: Bella Abramovna Subbotovskaya Ⓟ

##### Died:

- 1613: Duncan Liddel Ⓟ
- 1851: Olinde Rodrigues Ⓟ
- 1853: Robert Anstice Ⓟ
- 1907: William Thomson Ⓟ
- 1912: Spiru Haret Ⓟ
- 1940: Alicia Boole Stott Ⓟ
- 1964: Jurjen Koksma Ⓟ
- 1976: Archil Kirillovich Kharadze Ⓟ
- 1978: Friedrich Horn Ⓟ
- 1999: Jürgen Moser Ⓟ
- 2002: Aleksei Vasilevich Pogorelov Ⓟ

#### Quotation of the day

##### From William Thomson

When you measure what you are speaking about and express it in numbers, you know something about it, but when you cannot express it in numbers your knowledge about is of a meagre and unsatisfactory kind.