Born circa 1620 in Eutin; died 1687 in Paris. German mathematician, astronomer, and engineer.
Mercator studied and then worked in Copenhagen. In 1660 he moved to London, where he was made a member of the Royal Society. He later worked in Paris. His principal mathematical work, Logarithmotechnia (1668), contains an expansion of In (1 + x) in a series, which was the first (after geometric progressions) example of expansion in a power series.