an eminent mathematician of the seventeenth century, was born at Holstein in Denmark, and came about the time of the Restoration to England, where he lived many years. He was admitted a fellow of the Royal Society, and endeavoured to reduce astrology to rational principles. He published several works, particularly Cosmographia. He also gave the quadrature of the hyperbola by an infinite series, which was the first instance in the learned world of a series of this sort derived from the particular nature of the curve, and that in a manner equally new and refined.

Mercator's Sailing is that which is performed by Mercator's chart.