Born: 1620 in Eutin, Schleswig-Holstein, Denmark (now Germany)
Died: 14 Jan 1687 in Paris, France
Nicolaus Mercator entered the University of Rostock in 1632. He received a degree in 1641, then went to Leiden for a short period. After his return to Rostock in 1642 he was appointed to a post in the university.
In 1648 Nicolaus moved to the University of Copenhagen but, after working there for six years, he had to leave when the university was closed due to the plague. From this time on things were not too good for him.
He went to England in 1660 attempting to bring in some money and did some private tutoring. He was recognised in England however since he was elected a Fellow of the Royal Society in 1666. This was on the strength of a pendulum clock which Mercator designed to work at sea and thus be used to determine longitude. He also made measurements of air pressure for the Royal Society.
In 1682 he moved to France, this time with a specific position, namely to design the waterworks at Versailles.
While he was working at Copenhagen, Mercator published a number of textbooks on spherical trigonometry, geography and astronomy. These were Trigonometria sphaericorum logarithmica (1651), Cosmographia (1651), and Astronomica sphaerica (1651). He published further works in astronomy while in England, for example Hypothesis astronomia nova (1664) and Institutiones astronomicae (1676).
Mercator discovered the well known series, sometimes called Mercator's series,
ln(1+x) = x - x2/2 + x3/3 - x4/4 + ...
He published this in Logarithmotechnia 1668. This series was also investigated by Mengoli.
There is some reason to confuse Nicolaus Mercator with Gerardus Mercator since Nicolaus also worked on Gerardus Mercator's map projection.
J J O'Connor and E F Robertson