Under his direction, 796,928 square miles of India were surveyed, including difficult mountainous, forest, and desert regions, often for the first time.

That post he held for seventeen years, in the course of which he much improved the survey system and rendered the results more readily accessible to the public.

In 1868 he transferred the preparation of the Atlas of India from England to Calcutta, selecting a staff of engravers there for the purpose, and encouraging John Bobanau Nicklerlieu Hennessey[6] to introduce the photo-zincographic process.

[7] Thuillier retired on 1 January 1878, and the secretary of state, in a despatch dated 18 July 1878, highly commended the energy and perseverance of his forty-one years' service, and congratulated him on the results.

Settling at Richmond, he was long a useful member of the Royal Geographical Society's council and came to be looked upon as the father of the East India Company's service.

[2] There are three portraits in oils: (1) by Mr. Beetham (1846), formerly owned by Sir Henry Thuillier; (2) by Mr. G. G. Palmer (1885), formerly in the surveyor-general's office, Calcutta; and (3) by Mrs. Rowley (1896), presented by her to his eldest daughter, Mrs.