The most important of these essays, however, was "On the Mathematical Construction of a Plough" in which he offered an original and practical solution to the problem of efficient plough design with special reference to the mouldboard. It was in the course of this essay that he challenged Thomas Jefferson's claim to have discovered the mathematical principles for constructing a mould-board of least resistance. This prompted one of Jefferson's nineteenth-century admirers to vilify Amos posthumously, though less partisan American critics subsequently declared Jefferson's design to be badly flawed. Amos's approach to plough construction, though it built on the work of others, particularly of John Bailey (1750–1819), earned him a place in the history of plough design. The readership for Amos's books during his lifetime was probably only a few hundred, though his articles in Young's "Annals of Agriculture" and the Board of Agriculture's "Communications" would certainly have reached a greater number, and reviews and cyclopedia entries would have extended knowledge of his ideas still further. Unlike many of the best-known pioneers of the Agricultural Revolution, men such as Thomas Coke, 1st Earl of Leicester, Jethro Tull and Sir John Sinclair), Amos had neither the wealth nor the social standing to promote his ideas, but his publications establish him as an important contributor to the development of improved and evidence-based agricultural practice in the late eighteenth and early nineteenth centuries. Amos's name and work appear repeatedly in nineteenth-century works on agriculture. Twentieth-century writers have tended to overlook Amos's contributions, but the following offer limited reference: