THE EIGHTEENTH CENTURY was a period of nearly continuous wars between European countries. Monarchies realigned, changing alliances and altering definitions of nation. As nations established, contested and extended empires, nation acted as a term that encompassed more ground than simple geographical identities. This was not a new process but its particular components in the eighteenth century included new elements. What defined Britain included four countries, a Hanoverian monarchy and overseas dominions; British interests were therefore also simultaneously European and global, spread across continents and oceans, manifested through conflicts with peoples and treaties with nations. Making the case for Britain as physically and politically European, a historian in 2006 commented: ‘I took the trouble to ask the Map Librarian at the British Library whether he knows of any map of Europe which does not contain Britain. His answer was no. He knows of no map of Europe that does not contain the British Isles.’ Physical maps co-exist with mental maps in complex ways. What difference did it make to add air to land and sea as a place where nations operated? How did a new aerial dimension map on to a world in which European nations jealously guarded interests and zealously extended possessions whenever they could?

In exploring the role of balloons in eighteenth-century war, one must try to understand the world as it was when they appeared. English minds were full of uncertainty about peace. ‘It has been easy for later historians to underestimate the instability and insecurity of eighteenth-century Britain,’ says N. A. M. Rodger, who argues that ‘The motives which first created a dominant English navy in the 1650s, and which kept the British fleet the largest in Europe, were overwhelmingly defensive.