Historians of science have richly documented the interconnections between science and empire in the nineteenth century. These studies primarily begin with Britain, Europe, or the United States at the center and have focused almost entirely on lands far off in the periphery--India or Australia, for instance. The spaces in between have received scant attention. Because use of the ocean in this period was infused with the doctrine of the freedom of the seas, the ocean was constructed as a space amenable to control by any nation that could master its surface and use its resources effectively. Oceans transformed in the mid-nineteenth century from highway to destination, becoming--among other things--the focus of sustained scientific interest for the first time in history. Use of the sea rested on reliable knowledge of the ocean. Particularly significant were the graphical representations of knowledge that could be passed from scientists to publishers to captains or other agents of empire. This process also motivated early government patronage of science and crystallized scientists' rising authority in society. The advance of science, the creation of empire, and the construction of the ocean were mutually sustaining.