Francis Bacon’s natural philosophy contains a whole series of interconnected concepts related to extension, such as “borders,” “leaps” and “orbs of virtue”. These Baconian concepts are still not fully understood and are in need of a detailed analysis. They do not derive from a general conception of physical or mathematical space, and are not explainable in terms of parts of matter and aggregates. Instead, they are somewhat mysteriously defined in terms of limits and boundaries of action. This article offers a (...) contextual investigation of Bacon’s extension relating concepts. I show that in adopting a particular strategy of deriving spatial properties and extension related concepts from a theory of action and force, Bacon follows in the footsteps of Gilbert’s magnetic philosophy. However, in contrast to the more traditional approaches of William Gilbert, Giovan Battista della Porta and Johannes Kepler, Bacon strips his extension-related concepts from most natural philosophical content and argues for a methodologically driven approach, leading to operational definitions. (shrink)