[seszett]

> a mathematician friend

Said mathematician was Charles Marie de La Condamine, maybe he isn't too well known abroad but the guy also discovered rubber (well, for the Occident of course, the natives knew it already), a malaria treatment, and measured the shape of the Earth (to confirm Newton's hypothesis that the poles would be flattened) in a great expedition to Peru.

So he's a reasonably important 18th century man who wasn't only a mathematician.