John Dalton in the Witness Box

Research into John Dalton’s interests and activities in Manchester and how they related to and impacted on his scientific investigations provides a fuller picture of his life and achievements. This paper draws attention to Dalton’s role as an expert witness in legal cases ranging from his appearances in local inquests to significant legal cases in London, activities that have not been recognised as part of his professional persona. Attention is drawn to Dalton’s methods of investigation as well as his presentation of scientific evidence in the courtroom. In extending the historical record these insights modify Dalton’s professional persona outside the laboratory that has tended to focus on his activities associated with the Manchester Literary and Philosophical Society.