One of the earliest ideas on the circular flow was explained in the work of 18th century Irish-French economist Richard Cantillon,[2] who was influenced by prior economists, especially William Petty.[6] Cantillon described the concept in his 1730 Essay on the Nature of Trade in General, in chapter 11, entitled "The Par or Relation between the Value of Land and Labor" to chapter 13, entitled "The Circulation and Exchange of Goods and Merchandise, as well as their Production, are Carried On in Europe by Entrepreneurs, and at a Risk." Thornton eds. (2010) further explained: