1641 in science

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
• July 30 – Regnier de Graaf, Dutch physician and anatomist who discovered the ovarian follicles, which were later named Graafian follicles
• September 26 – Nehemiah Grew, English botanist and physician who made some of the early microscopical observations of plants

  Deaths

• January 3 – Jeremiah Horrocks, English astronomer
• March 8 – Xu Xiake, Chinese explorer and geographer
• July 5 – Simon Baskerville, English physician
• Guy de La Brosse, French physician and botanist