## Mathematicians Of The Day

### 18th September

##### Born:

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

##### Died:

- 1783: Leonhard Euler (poster)
- 1891: William Ferrel (poster)
- 1896: Hippolyte Fizeau (poster)
- 1977: Paul Bernays (poster)
- 2002: Siobhán Vernon (poster)

#### Quotation of the day

##### From Leonhard Euler

Notable enough, however, are the controversies over the series 1 - 1 + 1 - 1 + 1 - ... whose sum was given by Leibniz as 1/2, although others disagree. ... Understanding of this question is to be sought in the word "sum"; this idea, if thus conceived -- namely, the sum of a series is said to be that quantity to which it is brought closer as more terms of the series are taken -- has relevance only for convergent series, and we should in general give up the idea of sum for divergent series.