252 THREE CRUISES OF THE " BLAKE." 



The first scientific basis for the exploration of the Gulf 

 Stream was undoubtedly due to Franklin. At the time he was 

 Postmaster-General of the Colonies, his attention was called to 

 the fact that the royal mail packets made much longer passages 

 to and from Europe than the trading vessels of Massachusetts 

 and Rhode Island. On talking the matter over vrith. Captain 

 Folger of Nantucket, he first learned the existence of a strong 

 easterly current, of which the New England captains took 

 advantage in going to Europe, and which they avoided by 

 sailing a northerly course on the home voyage. Folger also 

 called Franklin's attention to the fact that this current was a 

 warm one.^ He and Dr. Blagden becoming interested in the 

 question, Franklin set out to ascertain the size of the current 

 and its temjDerature. Soon after, Frankhn published the first 

 chart of the Gulf Stream (Fig. 173), for the benefit of navi- 

 gators, from information obtained from Nantucket whalemen, 

 who were extremely familiar with the Gulf Stream, its course, 

 strength, and extent. 



From the time of Franklin until the problem of the Gulf 

 Stream was again attacked, in* 1845, by Franklin's descendant. 

 Prof. A. D. Bache of the United States Coast Survey, many 

 ingenious theories were pubhshed, but nothing was added to our 

 knowledge of the origin and structure of the Gulf Stream. 

 Humboldt, Arago, and others attempted to trace in the Gulf 

 Stream a secondary effect of the tradewinds, and of the rota- 

 tion of the earth. The officers of arctic expeditions sent to 

 Spitzbergen did not fail to see the effect of a mass of warm 

 water passing northward, and Von Baer was among the first to 

 consider this body of water as an eastern extension of the Gulf 

 Stream. Meanwhile the arctic explorers of Baffin's Bay and 

 western Greenland found themselves baffled in their efforts to 

 reach high latitudes by the powerful southerly current, carry- 

 ing with it fields of ice or huge icebergs, which had found their 

 way south below the southern limits of the Banks of Newfound- 

 land, and even beyond the latitude of Cape Cod and Nantucket 

 Shoals. 



^ It was noticed by Lescarbot, in 1605, both north and south of it the water of 

 that far north there was a mass of warm the Atlantic was cooler, 

 water moving towards the east, and that 



