Katherine Jones, Viscountess Ranelagh, British scientist (died 1691)

Katherine Jones, Viscountess Ranelagh, also known as Lady Ranelagh, was an Anglo-Irish scientist in seventeenth-century Ireland and England. She was also a political and religious philosopher, and a member of many intellectual circles including the Hartlib Circle, the Great Tew Circle, and the Invisible College. Her correspondents included Samuel Hartlib, Edward Hyde, William Laud, Thomas Hyde, and John Milton. She was the sister of Robert Boyle and is thought to have been a great influence on his work in chemistry. In her own right, she was a political and social figure closely connected to the Hartlib Circle. Lady Ranelagh held a London salon during the 1650s, much frequented by virtuosi associated with Hartlib.

March 22 is the 81st day of the year in the Gregorian calendar; 284 days remain until the end of the year.