Upon its publication in 1849, the British Admiralty's Manual of Scientific Enquiry: Prepared for the Use of Her Majesty's Navy and Adapted for Travellers in General appeared to represent a radical departure from the increasingly professionalized scientific societies. It invited travelers interested in scientific observation not only to practice the Admiralty's own methods for collecting scientific data, but also to send their results to Whitehall, contributing directly to the wealth of knowledge that represented Britons at the edges of the empire. Looking at the Manual within the context of its publication and marketing, this article examines how the Admiralty's popular guidebook legitimized its position as a popular scientific primer, and also how the Admiralty's reactions to the materials it received showed popular science as a site of cultural contention between institution and individual, ownership of and access to knowledge.