EMANCIPATION--BLACK AND WHITE. (The _Reader_, May 20th, 1865) 23 III. A LIBERAL EDUCATION: AND WHERE TO FIND IT. (An Address to the South London Working Men's College, delivered on the 4th of January, 1868, and subsequently published in _Macmillan's Magazine_) 31 IV. SCIENTIFIC EDUCATION: NOTES OF AN AFTER-DINNER SPEECH. (Delivered before the Liverpool Philomathic Society in April 1869, and subsequently published in _Macmillan's Magazine_) 60 V. ON THE EDUCATIONAL VALUE OF THE NATURAL HISTORY SCIENCES. (An Address delivered at St. Martin's Hall, on the 22d July, 1854, and published as a pamphlet in that year) 80 VI. ON THE STUDY OF ZOOLOGY. (A Lecture delivered at the South Kensington Museum, in 1861, and subsequently published by the Department of Science and Art) 104 VII. ON THE PHYSICAL BASIS OF LIFE. (A Lay Sermon delivered in Edinburgh, on Sunday, the 8th of November, 1868, at the request of the late Rev. James Cranbrook; subsequently published in the _Fortnightly Review_) 132 VIII. THE SCIENTIFIC ASPECTS OF POSITIVISM. (A Reply to Mr. Congreve's Attack upon the preceding Paper. Published in the _Fortnightly Review._ 1869) 162 IX. ON A PIECE OF CHALK. (A Lecture delivered to the Working Men of Norwich, during the Meeting of the British Association, in 1868. Subsequently published in _Macmillan's Magazine_) 192 X. GEOLOGICAL CONTEMPORANEITY AND PERSISTENT TYPES OF LIFE. (The Anniversary Address to the Geological Society for 1862) 223 XI. GEOLOGICAL REFORM. (The Anniversary Address to the Geological Society for 1869) 251 XII. THE ORIGIN OF SPECIES. (The _Westminster Review_, April 1860) 280 XIII. CRITICISMS ON "THE ORIGIN OF SPECIES." (The _Natural History Review_, 1864) 328 XIV. ON DESCARTES' "DISCOURSE TOUCHING THE METHOD OF USING ONE'S REASON RIGHTLY AND OF SEEKING SCIENTIFIC TRUTH." (An Address to the Cambridge Young Men's Christian Society, delivered on the 24th of March, 1870, and subsequently published in _Macmillan's Magazine_) 351 LAY SERMONS, ADDRESSES, AND REVIEWS. I. ON THE ADVISABLENESS OF IMPROVING NATURAL KNOWLEDGE. This time two hundred years ago--in the beginning of January, 1666--those of our forefathers who inhabited this great and ancient city, took breath between the shocks of two fearful calamities, one not quite past, although its fury had abated; the other to come.