1641 in science
- 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.
Editor, please review this reference, it conflicts with another wikipedia reference, citing samuel HOPKINS (not winslow) from pittsford vermont as the first patent owner
- 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)
- 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)