1698 in science

The year 1698 in science and technology involved some significant events.

Astronomy

Christiaan Huygens, in his posthumously published book Kosmotheoros, argues that other planets in the Solar System could contain extraterrestrial life, starting a debate that extends into the 21st century.

November – HMS Paramour sets sail under the command of Edmond Halley on the first purely scientific voyage by an English naval vessel, to investigate magnetic declination.

January 11 – April 21 – Tsar Peter the Great of Russia visits England as part of his Grand Embassy, making a particular study of shipbuilding.
July 25 – English engineer Thomas Savery obtains a patent for "A new invention for raising of water... by the impellent force of fire", a steam pump.
November 14 – First Eddystone Lighthouse illuminated, the first rock lighthouse in Europe.
The piano is invented by Italian Bartolomeo Cristofori, originally named the "piano et forte".
A metronome is developed as a machine to measure musical tempo.

November – Tani Jinzan, astronomer and calendar scholar, observes a fire destroy Tosa in Japan at the same time as a Leonid meteor shower, taking it as evidence to reinforce belief in the "Theory of Areas".