Dr Traill made a report to the Society of experiments made by him in 1832 at Liverpool and Manchester on magnetic intensity, measured by the oscillations of the horizontal needles belonging to the Society, which had been sent to him for that purpose. The reporter also stated the result of a series of experiments made by Professor Oersted and himself in Liverpool in 1823, which is important, as having been made use of by Professor Hansteen in constructing his isodynamic magnetic lines for Great Britain.