Studying the networks behind the spread of knowledge is an area of growing importance for the history of science, with far-reaching implications for how we view the development of ideas as a collaborative process. The recent launch of the John Henslow Correspondence Project on the Epsilon website places a sometimes overlooked figure at the centre of a web of correspondence, linking Henslow to many of the most important figures and trends in nineteenth-century scientific thought.

Best known as ‘Darwin’s mentor’, Henslow’s influence was fundamentally important to his student, providing him with many of the ideas and opportunities which enabled the development of his theories – notably recommending him for a place on the voyage of the Beagle. Henslow was also a hugely important figure in his own right who, as professor of Botany and Mineralogy at Cambridge, was involved in the creation of the University Herbarium and the foundation of the Botanic Garden at its present site. His letters reveal a figure who was deeply embedded in the networks of discourse which lay at the heart of many cutting-edge movements of the time, from plant science and geology through to archaeology and reformist political causes, such as Catholic emancipation.

Epsilon is the online home for the correspondence collections of many prominent nineteenth-century scientific figures, including the Darwin Correspondence Project, but its aims are much broader than this. As a cross-searchable platform, Epsilon encourages a movement away from the individual correspondence collection towards a more general flow of ideas. This process also foregrounds the role of the researcher in deciding the parameters for searches and finding new connections across collections. By including the Henslow material in Epsilon we know we are taking part in a process whereby the role of the individual is contextualised in terms of the connections they hold with others, revealing and encouraging the sharing processes that lead to discovery.

The letters are also important as a dataset. They now form the basis of a Python course on natural language processing set up by Mary Chester-Kadwell, a Senior Software Engineer working with Cambridge Digital Humanities. Aimed at a wide audience, the course provides a grounding in named entity recognition processes, giving participants the tools to extract information from a dataset using machine learning techniques. The course is available on GitHub here.

The transcription and collation of the letters has taken place over a 15-year period, starting with those held by the University Library, and 1030 have been made public as part of this initial launch. Much more information on Henslow and his correspondence is available on the University Library Special Collections blog. We are always looking for new letters and are confident in the knowledge that there is still a great deal of unseen material in the global archive, so any contributions are gratefully received!