on without it." "His peculiar system of philosophy," says Mr. Spedding in another preface, "that is to say, the peculiar method of investigation, the "_organum_," the "_formula_," the "_clavis_," the "_ars ipsa interpretandi naturam_," the "_filum Labyrinthi_," or by whatever of its many names we choose to call that artificial process by which alone he believed man could attain a knowledge of the laws and a command over the powers of nature--_of this philosophy we can make nothing_. If we have not tried it, it is because we feel confident that it would not answer. We regard it as a curious piece of machinery, very subtle, elaborate, and ingenious, but not worth constructing, because all the work it could do may be done more easily another way."--_Works_, iii. 171. What his method really was is itself a matter of question. Mr. Ellis speaks of it as a matter "but imperfectly apprehended." He differs from his fellow-labourer Mr. Spedding, in what he supposes to be its central and characteristic innovation. Mr. Ellis finds it in an improvement and perfection of logical machinery. Mr. Spedding finds it in the formation of a great "natural and experimental history," a vast collection of facts in every department of nature, which was to be a more important part of his philosophy than the _Novum Organum_ itself. Both of them think that as he went on, the difficulties of the work grew upon him, and caused alterations in his plans, and we are reminded that "there is no didactic exposition of his method in the whole of his writings," and that "this has not been sufficiently remarked by those who have spoken of his philosophy."