Mill’s _Political Economy_ is the only English treatise that can be compared with the _Wealth of Nations_. Indeed in his preface Mill challenges the comparison, but adds that “political economy, properly so-called, has grown up almost from infancy since the time of Adam Smith.” He finds the _Wealth of Nations_ “in many parts obsolete, and in all imperfect,” and though he speaks generously enough of Adam Smith’s “admirable success in reference to the philosophy of the [eighteenth] century,” it is plain from this preface and from the autobiography that the later economist felt he could look down upon the earlier from the serene temples of increased knowledge and better social ideas. Mill’s confidence was not only justified for the time being by unqualified success in the sense that his own book at once became, and remained for a generation, the principal text-book of English students, it was also based upon what appear at first sight to be enormous advantages. A more logical and systematic arrangement is adopted. Errors are corrected; digressions are few; and in order to attain scientific exactitude, historical illustrations from the conditions and experience of nations are replaced by more precise instances of imaginary societies labelled A, B, C. Technical terms and definitions make it easy for the student to move lightly about in an artificial atmosphere. But in this realm of political economy, is it not well to keep a foot, or at least an eye, on the ground? In Mill’s treatise there is a danger of mistaking words for things. It is never so in Smith’s inquiry. He gave twenty years to a task for which Mill could hardly spare as many months. With a gift for exposition, certainly not inferior, he had what Mill had not, a love of the concrete, a faculty for the picturesque, and withal a nervous force and vigour in argument quite peculiar to himself. It has been said that Smith hunted his subject with the inveteracy of a sportsman. With a wonderful knowledge of history, law, philosophy, and letters, he combined an intuitive insight into the motives of men and the unseen mechanism of society. At the same time, by restricting his horizon to wealth and its phenomena, he was able to see how men always had acted and always would act under certain circumstances, and by what rules public finance should be governed. This is the secret of his success in making political economy queen of the useful arts, and in raising her alone among political studies to the dignity of a science. “I think,” said Robert Lowe, “that Adam Smith is entitled to the merit, and the unique merit, among all men who ever lived in the world, of having founded a deductive and demonstrative science of human actions and conduct.” True, he is not a systematic writer. He does not shine, as so many inferior geniuses have shone, in the art of comparing, correlating, and harmonising the great truths which it is his glory to have discovered and illustrated.