Among the contemporaries of Stewart were the French Economists, or, as they have lately been called, the Physiocrats, forming the school founded by Quesnay. With the exception, however, of Turgot, they wrote on the whole art of government. Their works, indeed, contain treatises on Political Economy according to my third proposed definition, that is to say, “on the institutions and habits most conducive to that production, accumulation, and distribution of wealth, which is most favourable to the happiness of mankind;” but they contain much more. Quesnay and his followers lived in a country subject to political institutions, of which many were mischievous, more were imperfect, and all were unsettled. That the existing system of government was bad, every one acknowledged. The economists believed that they had discovered why it was bad. They believed that they had discovered that agriculture is the only source of wealth, and rent the only legitimate source of public revenue. And they proposed, therefore, to substitute for the innumerable taxes on importation, on exportation, on transit, on production, on sale, on consumption, and on the person of man, which then formed the fiscal system of France, a single tax on the rent of land. So far their precepts were founded on the science of Political Economy. But when they proposed the separation of legislative and judicial functions, and required the whole legislative power to center in an absolute hereditary monarch, they drew their premises from other branches of mental science. I have said that Turgot was an exception; and it is remarkable, that the only man among the disciples of Quesnay who was actually practising Political Economy as an art, is the only one who treated its principles as a science. His “Réflexions sur la Formation, et la Distribution des Richesses,” published in 1771, is a purely scientific treatise. It contains not a word of precept; and might have been written by an ascetic, who believed wealth to be an evil.