In this point of view the appendix annexed to the lectures is also valuable; and the four copious appendixes or dissertations following the edition of Reid's works, are more valuable still. How far Sir W. Hamilton has there furnished good proof of his own doctrines on External Perception, and on the Primary Qualities of Matter, we shall not now determine; but to those who dissent from him, as well as to those who agree with him, his reasonings on these subjects are highly instructive: while the full citations from so many other writers contribute materially not only to elucidate the points directly approached, but also to enlarge our knowledge of philosophy generally. We set particular value upon this preservation of the traditions of philosophy, and upon this maintenance of a known perpetual succession among the speculative minds of humanity, with proper comparisons and contrasts. We have found among the names quoted by Sir W. Hamilton, and, thanks to his care, several authors hardly at all known to us, and opinions cited from them not less instructive than curious. He deserves the more gratitude, because he departs herein from received usage since Bacon and Descartes. The example set by these great men was admirable, so far as it went to throw off the authority of predecessors; but pernicious so far as it banished those predecessors out of knowledge, like mere magazines of immaturity and error. Throughout the eighteenth century, all study of the earlier modes of philosophizing was, for the most part, neglected. Of such neglect, remarkable instances are pointed out by Sir W. Hamilton. While speaking about the general merits and philosophical position of Sir William Hamilton, we have hitherto said nothing about those of Mr Mill. But before we proceed to analyze the separate chapters of his volume, we must devote a few words to the fulfilment of another obligation.