Schiehallion Experiment: How Astronomers Weighed The Earth (opens in new tab)

In the summer of 1774, a team of British astronomers working under the patronage of the Royal Society established camp at the foot of a lonely mountain in the Scottish Highlands to conduct one of the most ingenious scientific experiments of the 18th century. Armed with telescopes, pendulums, quadrants, barometers, and delicate measuring rods, these men were attempting to weigh the Earth.