XXll INTRODLX^TION. 



for many suggestions relating to the history of the discovery of 

 the Gulf Stream. 



The commanders of the " Blake," Lieut.-Commander Sigsbee 

 and Commander Bartlett, were ever ready to promote the special 

 interests of the cruise during my connection with the vessel, and 

 they were most cordially supported by the officers and crew in 

 this novel work, so foreign to theii* usual routine. 



In arranging the following sketch of the work of the " Blake " 

 expeditions, I have collected in different chapters what I had to 

 say regarding the special subjects of which they treat, based 

 upon the experience gained during the voyages with which I 

 have been associated. The greater part of these chapters has 

 been in type for more than two years ; this will account for 

 some anachronisms, and for some omissions of reference to pub- 

 lications which would otherwise have been noticed. While of 

 course dealing with the subject of Thalassography as a whole, 

 I have avoided as far as possible all unimportant comparative 



work. 



ALEXANDER AGASSIZ. 

 Museum of Comparative Zoology, 

 Cambridge, December, 1887. 



