Abstract
Bamburgh Castle Library was a charity library kept in the historic castle on England's north-east coast. An examination of the borrowers' register, together with other archival sources regarding the library, from the early nineteenth century reveals a strong interest in different types of scientific literature. In 1800 scientific borrowings were dominated by the upper classes, whereas by 1810 the middle classes had become much more prominent as borrowers of scientific books. This change in usage links into the 'marginality thesis' in the history of science, which focuses on the emergence of a middle-class culture in Britain from a once 'marginalized' social formation.