title: 1641 in science
text: # 1641 in science
  
  The year 1641 in science and technology involved some significant events.
  
  ## Medicine
  
  * Nicolaes Tulp's Observationes Medicae is published in Amsterdam.
  
  ## Technology
  
  * The sealed thermometer is developed with Ferdinand II, Grand Duke of Tuscany, using a glass tube containing alcohol, which freezes well below the freezing point of water.
  * Samuel Winslow is granted the first patent in North America by the Massachusetts General Court for a new saltmaking process.
  
  ## Births
  
  * March – Menno van Coehoorn, Dutch military engineer (died 1704)
  * July 30 – Regnier de Graaf, Dutch physician and anatomist who discovered the ovarian follicles, which were later named Graafian follicles (died 1673)
  * September 26 – Nehemiah Grew, English botanist and physician who made some of the early microscopical observations of plants (died 1712)
  
  ## Deaths
  
  * January 3 – Jeremiah Horrocks, English astronomer (born 1618)
  * March 8 – Xu Xiake, Chinese explorer and geographer (born 1587)
  * July 5 – Simon Baskerville, English physician (born 1574)
  * Guy de La Brosse, French physician and botanist (born c. 1586)
  