Empire of Experiment offers a vivid, ground-level history of early modern science as it moved through the British Empire before 1815. Drawing on previously unpublished diaries, journals, and newly discovered correspondence, Larry Stewart reconstructs a world shaped not only by celebrated thinkers but by practitioners, craftsmen, and artisans who carried experimental knowledge across imperial networks and into public life. At the center of his study is James Dinwiddie, long dismissed by contemporaries yet present at pivotal moments, including the Macartney embassy to Qianlong China. Dinwiddie's writings provide a rare eyewitness account of scientific practice amid imperial expansion, from London's workshops to distant colonial encounters during the age of revolution and war. With this book, Stewart uncovers the lived experience of experiment. He reveals how science operated across global spaces and contested terrains, offering a fresh perspective on the relationship between knowledge, empire, and everyday practice.