Measure of the Earth

The Enlightenment Expedition That Reshaped Our World

In the early eighteenth century, at the peak of the Enlightenment, an unlikely team of European scientists and naval officers set out on the world’s first international, cooperative scientific expedition. Intent on making precise astronomical measurements at the Equator, they were poised to resolve one of mankind’s oldest mysteries: the true shape of the Earth.

In Measure of the Earth, award-winning science writer Larrie D. Ferreiro tells the full story of the Geodesic Mission to the Equator for the very first time. It was an age when Europe was torn between two competing conceptions of the world: the followers of René Descartes argued that the Earth was elongated at the poles, even as Isaac Newton contended that it was flattened. A nation that could accurately determine the planet’s shape could securely navigate its oceans, giving it great military and imperial advantages. Recognizing this, France and Spain organized a joint expedition to colonial Peru, Spain’s wealthiest kingdom. Armed with the most advanced surveying and astronomical equipment, they would measure a degree of latitude at the Equator, which when compared with other measurements would reveal the shape of the world. But what seemed to be a straightforward scientific exercise was almost immediately marred by a series of unforeseen catastrophes, as the voyagers found their mission threatened by treacherous terrain, a deeply suspicious populace, and their own hubris.

A thrilling tale of adventure, political history, and scientific discovery, Measure of the Earth recounts the greatest scientific expedition of the Enlightenment through the eyes of the men who completed it—pioneers who overcame tremendous adversity to traverse the towering Andes Mountains in order to discern the Earth’s shape. In the process they also opened the eyes of Europe to the richness of South America and paved the way for scientific cooperation on a global scale.