[3] He became an expert in theological books, especially hymn-books, later publishing reprints of some rare hymn-writers of the 17th and 18th century.
He did not learn to write until 1840, but then began to edit and publish hymnological books, including A Comprehensive Index of ...
Original Authors and Translators of Psalms and Hymns (1860, 2nd enlarged edn 1863).
This brought him wide respect as a hymnologist, and he was consulted by many hymn-book editors, including C. H. Spurgeon, Josiah Miller, Sir Roundell Palmer (Lord Selbourne), and the editors of Hymns Ancient and Modern.
He was a careful scholar, though not always accurate, and he pioneered a branch of hymnological studies which many have since followed.