The project entails an investigation into the geography in and of Victorian scientific practice by examining the Zambesi Expedition (1858-1864). The official purposes of this expedition, funded by the British Foreign Office, were to catalogue the natural resources of the regions adjacent to the Zambezi River in order to identify new sources of raw materials for British industry and to introduce commercial markets to supplant the slave trade. To better understand the social practices used to achieve these goals, a survey was made of relevant scientific literature to identify published analyses of the data and specimen collections produced by the Expedition’s staff. Fieldwork practices are examined in depth and an ideology of technology, expressed in different ways, is shown to have structured the encounters between the British and the locals. Power differentials were apparent in the field when the information possessed by local informants was required for the success of the scientific goals of the expedition. Credibility in the field became a tenuous quality negotiated between local informants, explorers and the metropolitan scientific community. These results will lead to a richer understanding of the practices of Victorian science and the role of science in British imperial projects.