c)L. 



INTRODUCTION. 



The Physical Geography of the Sea is a new department of 

 human knowledge. It has resulted from that beautiful and 

 admirable system of physical research, in which all the maritime 

 nations have agreed to unite ; and for the furtherance of which 

 bureaux have been established, especially in Holland, England, 

 France, and the United States. 



Consequently, research has become very active in this field ; 

 it is diligent, too ; and in proportion to that activity and that 

 diligence has been the advancement of our knowledge concerning 



the PHYSICAL GEOGRAPHY OF THE SEA AND ITS METEOROLOGY. It 



may be doubted whether progress in any department of science 

 has been more rapid than it has been in this. 



The first treatise upon this subject appeared in America six 

 years ago. Since then such has been the richness of the harvest 

 of facts gathered, that the work has undergone frequent amend- 

 ments and improvements ; indeed, within that time it has been 

 almost entirely re-written thrice. This re-writing was necessary 

 because it is a main motive with the author to have the work 

 keep pace with the science itself. The consequence has been, 

 that each re-cast has really made a new work of it. 



The present edition is not only greatly enlarged above its pre- 

 decessors, but it is believed to be greatly enriched and improved 

 also. It may even be doubted whether in the variety, extent, 

 and value of the information now for the first time presented 

 touching the sea and air, this edition is not so far in advance of 

 former editions as really to make this a new work. \Vliere error 

 has been found in previous editions, it has been corrected in this, 

 — where further research has confirmed opinions that in tliem 

 were ventured as such, the confirmation is here given. 



The present edition contains a number of chapters entirely new 

 and not to be found in any of its predecessors. Most, if not all 



