Michael Florent van Langren was a Belgian astronomer and cartographer in the service of the Spanish Monarchy. He attempted to determine longitude and made observations of the comet of 1652, C/1652 Y1. He also made various maps of the Spanish Netherlands and produced plans for a port near Dunkirk.
Background
Michael Florent van Langren was born c. 1598 in Mechlin or Antwerp, Belgium. He was baptized on April 27, 1598. Very little is known of Langren’s life. His grandfather, Jacob Floris van Langren was born in Gelderland but moved to the Southern Netherlands and later to Amsterdam, where his sons Arnold and Henry were born. His father, Arnold Florent van Langren, was an archducal spherographer. Langren's parents, who were Catholics, had left Holland before 1600 for the Spanish Netherlands and finally settled in Brussels in 1611.
Education
Langren probably was educated in Brussels, but nothing is known about his education.
Career
Like his father, Langren became a royal cosmographer and mathematician. The primary goal of his research was to discover a method of determining longitude at sea. As early as 1621 he attempted to do this by means of lunar observations, basing his procedure on the darkenings and illuminations of the lunar mountains; this approach obviously required good maps of the moon and a precise toponymy. In 1625, at Dunkirk, he presented his method to the archduchess Isabelle. The following year he requested and received assistance to travel to Spain in order to present his method to the king and to call attention to his books Tábulas astronómicas y hydrográphicas, which are now lost. The journey lasted from 1631 to 1634; the king promised to finance the publication of his observations. The work Advertencias de Miguel Florencio Van Langren a todos los professores y amadores de la mathemática appeared in Madrid about 1634.
Langren continued his investigations in Brussels, publishing a Calendarium perpetuum in 1636 and La verdadera longitud por mar y tierra in 1644. Before February 15, 1645, he submitted to the Privy Council a manuscript map of the moon in support of his request for a privilege to publish it. The map, engraved by Langren himself, appeared in May 1645. As is indicated by the title, Plenilmii Lumina Austríaca Philippica, it presents the full moon and, as is stated in Langren’s long legend, it was to be a part of a series of maps showing thirty phases of the moon. These maps, a veritable selenography, were prepared but were never published, owing to the death of Langren’s patron, Erycius Puteanus, and to the wars. Langren also published a text on the comet of 1652, Repraesentatio partis caeli quam cometa.
Langren also drew geographical maps, several of which have been lost. They included one of a canal from the Meuse to the Rhine, one of the archdiocese of Mechlin, one of Luxembourg, and one of the three parts of the former duchy of Brabant; the latter three appeared in the Novus atlas of W.J. Blaeu. In addition, he provided maps and plans for projects for large public works.
In 1640, in Brussels, Langren published Tormentum bellicum trisphaerium, concerning a three-shot cannon. His studies and projects for a port to be constructed at Mardyck, near Dunkirk, date from 1624; and in 1653 he published, again in Brussels, Description particulière du Banc de Mardijck, which ran to two editions. His work on the harbor port of Ostend is set forth in Profytelijcken middel om de Zee-Haven van O os tende te verbe teren, in Briefve description de la ville el havre d'Oostende, and in Copies de la Vie, Xle et XlIIe lettre que don Juan d'Austriche a escrit à Michel-Florencio Van Langren. In 1661 he wrote a short treatise on the cleaning of the canals of Antwerp: Bewys van de alder-bequaemste ende profytelyckste inventie. His works concerning Brussels dealt with fortifications, canals, and means of protecting the city from the flooding of the Senne: Invention et proposition que Michel Florencio Van Langren a faict pour empescher le débordement de la rivière de Senne, Eenighe middelen om Brussel van de inondacien te bevryden, and Michael Florencio Van Langren sprekende stadt Brussel.
Achievements
As an engineer, a cartographer, and an engraver, Langren occupied a leading place in the Spanish Netherlands. As a selenographer, he was, like Hevelius, a pioneer. Circumstances did not permit him to develop his talents fully, and only a thorough study of his work can allow to arrive at a just appreciation of his achievements.
He named crater Langrenus on the Moon after himself, and the name has been preserved to our day.
