accustomed to leap over many of the intermediate links necessary for enabling other persons to reach his conclusions, and who, when at last he sits down to write, is unable to recover them. It was another great disadvantage to Hartley's theory, that its {xii} publication so nearly coincided with the commencement of the reaction against the Experience psychology, provoked by the hardy scepticism of Hume. From these various causes, though the philosophy of Hartley never died out, having been kept alive by Priestley, the elder Darwin, and their pupils, it was generally neglected, until at length the author of the present work gave it an importance that it can never again lose. One distinguished thinker, Dr. Thomas Brown, regarded some of the mental phenomena from a point of view similar to Hartley's, and all that he did for psychology was in this direction; but he had read Hartley's work either very superficially, or not at all: he seems to have derived nothing from it, and though he made some successful analyses of mental phenomena by means of the laws of association, he rejected, or ignored, the more searching applications of those laws; resting content, when he arrived at the more difficult problems, with mere verbal generalizations, such as his futile explanations by what he termed "relative suggestion." Brown's psychology was no outcome of Hartley's; it must be classed as an original but feebler effort in a somewhat similar direction. It is to the author of the present volumes that the honour belongs of being the reviver and second founder of the Association psychology. Great as is this merit, it was but one among many services which he rendered to his generation and to mankind. When {xiii} the literary and philosophical history of this century comes to be written as it deserves to be, very few are the names figuring in it to whom as high a place will be awarded as to James Mill. In the vigour and penetration of his intellect he has had few superiors in the history of thought: in the wide compass of the human interests which he cared for and served, he was almost equally remarkable: and the energy and determination of his character, giving effect to as single-minded an ardour for the improvement of mankind and of human life as I believe has ever existed, make his life a memorable example. All his work as a thinker was devoted to the service of mankind, either by the direct improvement of their beliefs and sentiments, or by warring against the various influences which he regarded as obstacles to their progress: and while he put as much conscientious thought and labour into everything he did, as if he had never done anything else, the subjects on which he wrote took as wide a range as if he had written without any labour at all. That the same man should have been the author of the History of India and of the present treatise, is of itself sufficiently significant. The former of those works, which by most men would have