He was a wealthy banker in India, owned large estates in Malaysia, served as a British military officer, and held a number of important public offices in British India.

His work showed that the so-called first issue of Kashmir was bogus, a feat which The London Philatelist called "...one of the most memorable and startling of accepted disclosures ever made in philately".

He was Managing Director of the Punjab Banking Co.[4] of Lahore, Karachi and Kashmir.

He served as ADC to the Commander-in-Chief and Viceroy of India, and for fifteen years was Lieutenant-Colonel in the 1st Punjab Volunteer Rifles.

[2] Masson contracted a serious illness while inspecting his estates in Penang and was obliged to return to London, where he died on 30 December 1915.