Papers relating to Perspective tracing and drawing instruments invented by Ronalds and others; Ronalds' electric telegraph; the development of ideas on galvanism; Ronalds' experiments with electric columns and their application to clockwork, with drawings of Ronalds' clock; notes and diagrams relating to the measurement of atmospheric electricity and the use of electrometers; Ronalds' system of aquatic propuylsion with notes, lists of patents and references etc; notes, drawings and cardboard models of geometric pens and other drawing instruments invented by Ronalds and others. There are also Ms notes on various other topics such as calculating machines and the National Debt.