1721 in science

The year 1721 in science and technology involved some significant events.

Medicine

 * The use of ether is developed as a pain-killer.
 * Lady Mary Wortley Montagu introduces the Ottoman Turkish method of inoculation against smallpox – variolation – to London.
 * Thomas Guy founds Guy's Hospital in London to treat "incurables" discharged from St Thomas'.

Psychology

 * A suggestion box is developed under the eighth shōgun of Japan, Yoshimune Tokugawa.

Technology

 * Richard Newsham of London obtains his first patent for a manual fire pump.

Deaths

 * September 11 – Rudolf Jakob Camerarius, German botanist (born 1665)