Correspondence, extracts from Ronalds diaries and newspaper cuttings concerning magnetical, meteorological and electrical instruments at the Kew Observatory 1848-1849, the Madrid Observatory 1851-1855 and the Radcliffe Observatory 1852-1856, with correspondence and memoranda on various scientific subjects pre-1853 and 1853-1862. Much of the correspondence is concerned with Ronalds' advice on setting up apparatus similar to that at Kew in other observatories. There is also a large number of items dating from the period when Ronalds travelled on the Continent enlarging his collection of electrical books and pamphlets.