CONTENTS 



i 



PAOE 



ON A PIECE OF CHALK [1868] 1 



(A Lecture delivered to the working men of 

 Norwich during the meeting of the British 

 Association.) 



II 



THE PROBLEMS OF THE DEEP SEA [1873] 37 



III 



ON SOME OF THE KESULTS OF THE EXPEDITION OF H.M.S. 



"CHALLENGER" F1875] 



IV 



7EAST [1871] .110 



