Whatley was the author of Principles of Trade, published in 1774, which expounded the benefits of laissez faire economics, which is similar in concept to free trade. Some sources claim Franklin co-authored the book with Whatley, while Franklin gives full credit to Whatley. However, according to historian Jared Sparks in his book The works of Benjamin Franklin, 1840, Sparks gives Franklin credit for the notes which are in the view of noted economist Jacob Viner, superior to the text, see footnote 97 for chapter 2, Studies in the Theory of International Trade,.
Whatley's portrait by an unknown painter is part of the Foundling Hospital art collection and can today be seen in the Picture Gallery at the Foundling Museum.
- Benedict Nicolson, "The Treasures of the Foundling Hospital," Clarendon Press, 1972, p. 60.
- Jacob Viner (1930). "Early English Theories of Trade". Journal of Political Economy: 404–457. doi:10.1086/254122.
- Nicolson, "Treasures of the Foundling Hospital," p. 60.