on the History of Greek Philosophy.—I. The Pre-Socratic Period. 1859-60;' and the second, 'Lectures on the History of Greek Philosophy.—II. The Socratic Period. 1860-61-62.' The remaining portion was mostly written on loose sheets; these were frequently revised and corrected: in some cases where later lectures have been incorporated with earlier ones, it is not easy to determine precisely how much of the earlier he intended to retain, or how much he considered superseded by the later. Here and there paragraphs are marked "Omit;" these the editor has judged right to exclude from the work, though not clearly certain whether the omission thus directed merely referred to the particular occasion of the lecture being delivered, or was meant to imply a purpose of rewriting or expunging the paragraphs. Some omissions have also been made of passages where the subject handled was not directly Greek Philosophy, but one which, though closely connected with it, has received full treatment in various other works; for instance, the lives of the more eminent philosophers. To include the biography of Socrates, Plato, and Aristotle, perfectly suitable as it was in lectures addressed to youthful learners, appeared unnecessary in a review of Greek Philosophy. This rule of exclusion, however, did not always seem applicable to the less illustrious occupants of a place in the history of metaphysical speculation. It appears from the MS. that the lecturer occasionally read to his class articles contributed by himself to the 'Imperial Dictionary of
