PREFACE vii 



plankton, or the American Tile-fish and the movements 

 of the GuK Stream ; and fm*ther that Oceanography has 

 practical applications, such as those bearing on the sea- 

 fisheries and the possible cultivation of our barren shores, 

 aU requiring further exploration, in the hope that man 

 in the future may become less of a hunter and more of a 

 farmer of the sea. 



I desire to record my grateful thanks to various colleagues, 

 assistants and students, with whom I have worked at 

 Liverpool and Port Erin, for information and co-operation 

 and for the use of some of their photographs of natural 

 objects taken in the laboratory or at sea. I would mention 

 especially Professor R. Newstead, Mr. Andrew Scott, Mr. 

 Edwin Thompson, Dr. Francis Ward, Mr. E. Neaverson and 

 Mr. A. Fleming. I am indebted also to Professor Kofoid of 

 California, Dr. Jules Richard of Monaco, Mr. James Chumley 

 of the " Challenger " office, the Editor of the Popular 

 Science Monthly and the Controller of H.M. Stationery 

 Office for their courtesy in lending me photographs or in 

 permitting me to reprint articles or illustrations. 



Finally, I would add that this book is associated in my 

 mind with the memory of my wife — the constant companion 

 by land and sea, in work and play, of close on thirty years — 

 who helped me to estabHsh the University Department of 

 Oceanography, who encouraged me to give the course of 

 lectures and frequently urged me to prepare them for 

 publication, and whose helpful criticism of the material in 

 its present form would have been invaluable. 



W. A. HERDMAN. 

 Liverpool, 



July, 1923. 



