Nicholas Mercator

Nicholas Mercator (about 1620 to 1687), known in German as Nikolaus Mercator or Kauffmann, was a seventeenth-century mathematician born in Eutin, in the Prince-Bishopric of Lubeck within the Holy Roman Empire. He was educated at Rostock and Leyden, lived in the Dutch Republic from 1642 to 1648, lectured at the University of Copenhagen from 1648 to 1654, and spent 1655 to 1657 in Paris before teaching mathematics in London from 1658 to 1682. In 1661 he observed a transit of Mercury with Christiaan Huygens and Thomas Streete, and in 1666 he was elected a Fellow of the Royal Society. He designed a marine chronometer for Charles II, and in 1682 Colbert invited him to help design the fountains at Versailles, where he died after a falling-out. He is best known for his treatise Logarithmo-technia of 1668, which described the Mercator series, and he was the first person to use the term natural logarithm. In music he gave the first precise account of 53 equal temperament.