 The Tableau économique (Economic Table) of François Quesnay (1758), which laid the foundation of the Physiocrat school of economics is credited as the "first precise formulation" of interdependent systems in economics and the origin of multiplier theory.In the tableau économique, one sees variables in one period (time "t") feeding into variables in the next period (time "t+1"), and a constant rate of flow yields geometric series, which computes a multiplier.The modern theory of the multiplier was developed in the 1930s, by Kahn, Keynes, Giblin, and others, following earlier work in the 1890s by the Australian economist Alfred De Lissa, the Danish economist Julius Wulff, and the German-American economist N. A. J. L. Johannsen.