The first political economists seeking to explain how markets determined prices modeled barter markets in which actors were much like Henner and the other traders in the shell egg futures ring: where a trader might be both buying and selling at the same time—buying wheat and selling wine, in these first models, or bidding for eggs in the future by offering a contract, as in Henner’s case. This renders ineffective the test that true prices result when buyers seek low prices and sellers, high ones. These early models, too, did not clear markets. Adam Smith, meanwhile, argued that market prices were not always the natural price that reflected the theoretical value of goods. Neoclassical theorists aimed to resolve this by proposing depersonalized, mathematically perfect market.