Following the death of Duncan, senior, in 1811, Sir Charles Forbes acted as his guardian.
In the years up to 1841, he wrote a number of history books about Russia, religious wars in France, and Guernsey.
[2] In 1846, he was editor of a newspaper called The Sentinel, and presented a petition to Parliament criticizing Frederic Festus Kelly, chief inspector of letter-carriers.
[3] In 1846, he wrote the tract "How to reconcile the rights of property, capital, and labour" for the Currency Reform Association.
[2][4] In 1847 he wrote a tract for the National Anti-Gold Law League, arguing that the size of the circulation should be determined by supply and demand.