In the next place, though the prominence which he gave to the doctrine of Induction was one of those novelties which are so obvious after the event, though so strange before it, and was undoubtedly the element in his system which gave it life and power and influence on the course of human thought and discovery, his account of Induction was far from complete and satisfactory. Without troubling himself about the theory of Induction, as De Rémusat has pointed out, he contented himself with applying to its use the precepts of common-sense and a sagacious perception of the circumstances in which it was to be employed. But even these precepts, notable as they were, wanted distinctness, and the qualities needed for working rules. The change is great when in fifty years we pass from the poetical science of Bacon to the mathematical and precise science of Newton. His own time may well have been struck by the originality and comprehensiveness of such a discriminating arrangement of proofs as the "Prerogative Instances" of the _Novum Organum_, so natural and real, yet never before thus compared and systematized. But there is a great interval between his method of experimenting, his "_Hunt of Pan_"--the three tables of Instances, "_Presence_," "_Absence_" and "_Degrees, or Comparisons_," leading to a process of sifting and exclusion, and to the _First Vintage_, or beginnings of theory--and say, for instance, Mill's four methods of experimental inquiry: the method of _agreement_, of _differences_, of _residues_, and of _concomitant variations_. The course which he marked out so laboriously and so ingeniously for Induction to follow was one which was found to be impracticable, and as barren of results as those deductive philosophies on which he lavished his scorn. He has left precepts and examples of what he meant by his cross-examining and sifting processes. As admonitions to cross-examine and to sift facts and phenomena they are valuable. Many of the observations and classifications are subtle and instructive. But in his hands nothing comes of them. They lead at the utmost to mere negative conclusions; they show what a thing is not. But his attempt to elicit anything positive out of them breaks down, or ends at best in divinations and guesses, sometimes--as in connecting Heat and Motion--very near to later and more carefully-grounded theories, but always unverified. He had a radically false and mechanical conception, though in words he earnestly disclaims it, of the way to deal with the facts of nature. He looked on them as things which told their own story, and suggested the questions which ought to be put to them; and with this idea half his time was spent in collecting huge masses of indigested facts of the most various authenticity and value, and he thought he was collecting materials which his method had only to touch in order to bring forth from them light and truth and power. He thought that, not in certain sciences, but