128 THE OCEAN RIVER 



nating hot and cold bands of water, corresponding to the cold- 

 water pools encountered by the packet Eliza and later con- 

 firmed by Rennell. Bache believed that the cold bands were 

 caused by mountain ranges on the ocean floor, which forced 

 the waters to split apart into separate streams. Later, as instru- 

 ments improved and more careful soundings were made, these 

 mountains were found to be nonexistent, and today we know 

 that the separate streams or veins are really eddies of the main 

 current. 



A simple but very eflrective aid to the slow and tedious 

 process of investigation was the use of floating indicators and 

 instruments for the direct measurement of currents. In its 

 simplest form this is nothing more than the timing and obser- 

 vation of drifting objects. The floating sea beans which stirred 

 adventurous instincts along the eastern shores of the Great 

 River in the early days of Atlantic exploration were the chance 

 forerunners of a vast quantity of floats of various types that 

 have since been thrown into the sea in the study of ocean 

 currents. The first deliberate use of this kind of measurement 

 was made in 1802, when special bottles with the time and 

 place of release recorded in them were thrown overboard from 

 the English ship Rainbow. 



The Prince of Monaco eighty years later became not only a 

 patron but an active devotee of the new science of oceanogra- 

 phy, and concentrated on a study of the eastern part of the 

 Gulf Stream. He had made large numbers of hollow copper 

 spheres, of which more than 900 were released between the 

 Azores and Newfoundland, over 500 in the ocean off the coast 

 of France, and 139 northwest of the Azores. Their movements 

 provided indisputable proof of branching currents that reached 

 from the western Atlantic to Ireland and Norway on the one 

 hand and to France and Africa on the other. Two of the floats 

 released off the coast of France drifted as far as the West 

 Indies. 



