ADAMS (George). AN ESSAY ON ELECTRICITY, explaining the principles of that useful science and describing the instruments to which is now added a letter to the author from Mr. John Birch... London, printed for the author by R. Hindmarsh and sold by the author, 1792. In-8 of 10-588 pages, half calf, smooth spine (English binding) Fourth edition illustrated with a folded frontispiece showing the author electrifying a child and 5 plates of instruments for experiments. Pitting to frontispiece and title.