## Mathematicians Of The Day

### 29th January

On this day in 1670, James Gregory wrote to John Collins:

Mr Barrow, in his Optics, showed himself a most subtle geometer, so that I think him superior to any that ever I looked upon: I long exceedingly to see his geometrical lectures, especially because I have some notions upon that same subject by me. I entreat you to send them to me presently as they come from the press, for I esteem the author more than you can easily imagine.

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##### Born:

- 1774: Olinthus Gregory Ⓟ
- 1810: Eduard Kummer Ⓟ
- 1817: William Ferrel Ⓟ
- 1888: Sydney Chapman Ⓟ
- 1928: Joseph Kruskal Ⓟ
- 1951: Olabisi Ugbebor Ⓟ

##### Died:

- 1715: Bernard Lamy Ⓟ
- 1905: François Folie Ⓟ
- 1905: Robert Tucker Ⓟ
- 1910: James Taylor Ⓟ
- 1984: John Whittaker Ⓟ
- 1999: Viktor Aleksandrovich Gorbunov Ⓟ
- 2010: Giovanni Prodi Ⓟ

#### Quotation of the day

##### From Eduard Kummer

It is greatly to be lamented that this virtue of the real integers that they can be decomposed into prime factors which are always the same for a given integer does not belong to the complex integers [of arbitrary cyclotomic number fields], for were this the case, the entire theory, which is still labouring under many difficulties, could easily be resolved and brought to a conclusion.