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