77/6? Cnlf Stream. 45 



current, being only superficial, did not affect the drift of the vessel 

 itself. That such is the case is also shown by the circumstance 

 that seaweed and drift-wood, found in such large quantities on the 

 outer edge of the Stream, are never, even when easterly winds pre- 

 vail, found on the inside, for in that case they would have to drift 

 up the Stream to cross it." 



Since the course of the Stream is north-east as far as New- 

 foundland and due east afterwards, it has been said that the banks 

 turn it. It is, however, probable that the banks themselves are 

 the effect, not the cause. For the icebergs, loaded with debris of 

 all kinds, brought down by the Northern Current, m«et and melt 

 in the warmer waters of the Stream, depositing their solid matter, 

 and thus forming the banks of Newfoundland. Could a cannon- 

 ball be shot from Florida to the British Tsles, its course would 

 describe an arc of a great circle, in consequence of the motion of 

 the earth round its axis. This is exactly the course of the Gulf 

 Stream, showing that the banks of Newfoundland have no influence 

 over it. With regard to the temperature of its waters, we find that 

 they are hottest at the top, less and less warm as we go deeper, 

 giving us reason to believe that there is a layer of cold water 

 between the warm waters and the earth's crust. Now cold water 

 is a bad conductor of heat, and it is clear that without this layer 

 the heat of the Stream itself would be absorbed by the earth, and 

 never alleviate the climate of Western Europe. As it is, the heat 

 carried from the tropical regions of Mexico and discharged over the 

 Atlantic would, as it has been computed, suffice to raise mountains 

 of iron from zero to the melting point, and kept in flow from them 

 a molten stream greater in volume than the waters daily discharged 

 from the Mississippi. To this heat Ireland is indebted for its name 

 of " Emerald Isle," while the harbour of St. John's, Newfoundland, 

 in the same latitude, has been, so late as June, blocked up with 

 ice. 



Its influence on commerce is not nearly so great now as when 

 mariners had no instruments on which they could rely, and no 

 propelling force but the winds and currents ; still it may easily be 

 imagined what in former days must have been the advantages gained 

 by sailors from a current uniformly flowing summer and winter, from 

 south to north. 



Some remarks were afterwards made by the President, advocat- 

 ing Herschel's view of the causes of the gulf stream. 



