An amateur scientist and musician, he published a book on magnetism in 1729 and a treatise on musical harmony in 1730, which was subsequently emended and re-issued by his teacher, Dr. Pepusch.

James and Anne had six sons and two daughters: On 10 November 1715 Lord Paisley was elected a Fellow of the Royal Society.

In 1729 he published a short treatise entitled Calculations and Tables Relating to the Attractive Virtue of Loadstones (according to the catalogue of the British Library), which presents the results of experiments he had made with lodestones (natural permanent magnets) of various sizes, each time measuring the mass of the loadstone and the weight of iron with which it can be armed, or that it can hold on its surfaces.

[19] Lord Paisley also studied music, taking lessons from Johann Christoph Pepusch, a well-known musician in his time.

In 1730 he published, based on Pepusch's teaching, anonymously and without his teacher's assent a booklet entitled "A Short Treatise on Harmony".

[26] On 17 October of that same year, George II issued a royal charter to the nation's first orphanage for abandoned children, the Foundling Hospital, of which Abercorn was one of the many founding governors.

[27] Abercorn died on 11 January 1744 at Cavendish Square, western London,[28] and was buried five days later in the Ormonde vault of the Henry VII Chapel of Westminster Abbey where his father had already been laid to rest.