As Astronomer Royal and president of the Royal Society respectively Nevil Maskelyne and Joseph Banks had a long and complex relationship, spanning more than forty years.
The two giants of late 18th century science were key members of the Board of Longitude and during the formative years of their friendship they were close, sometimes sharing smutty jokes in their letters to one another.
In 1774, Maskelyne became involved in an experiment designed to determine the Earth’s density, or put another way, the ‘weight of the world’.
The Schielallion experiment, as it came to be known, took place on a Scottish mountain named Sìdh Chailleann in Gaelic, meaning ‘Fairy Hill of the Caledonians’.
The venture was funded by the Royal Society under the auspices of the ‘Committee of Attraction’. Banks and Maskelyne were among the members.
The experiment benefited from scientific instruments that Captain James Cook had used during his first circumnavigation of the world in 1768-71, including the quadrant that was used to observe the 1769 transit of Venus from Tahiti. In fact, some of the Royal Society funds for the Schielallion experiment came from those left over by under-spend on the transit of Venus expedition.
Maskelyne’s ‘weigh the world’ experiment took place in the summer of 1774 and the following year one of the letters he wrote to Banks began by thanking the naturalist for information he had supplied about some of the rocks the astronomer collected on the mountain.
“I am very happy in finding your opinion so clearly in favor of Schehalliens being a Virgin Venus never submitted to the embraces of Vulcan, the God of Fire: the more estimable, & more attractive on that account!” Maskelyne wrote.
The two men’s lengthy correspondence tells us much about their relationship. Nine years later, in 1784, with Banks having become president of the Royal Society in 1778 and Maskelyne having been among a breakaway group that tried to depose him in late 1783, the tone of their exchanges is rather different. An intern working at the National Maritime Museum in Greenwich has found documents that reveal the depth of the schism between the two men at this time.