70 PLANTS, SEEDS, AND CURRENTS 



coasts of North Brazil, thence proceeding northward past the Guianas 

 to the West Indies. From the Admiralty Sailing Directions, Laugh- 

 ton's Physical Geography, and other works of reference, it is evident 

 that very high velocities, even of sixty miles a day, are at times 

 attained by this current on its way to Cape St. Roque. It is prob- 

 able, however, that an average rate of twenty to thirty miles is near 

 the truth. In the latter part of its course, along the coasts of North 

 Brazil and the Guianas, it nearly doubles its speed, flowing usually 

 from thirty to fifty miles a day and occasionally as much as seventy 

 or eighty miles. 



The behaviour of the drifting bottle is quite in agreement with the 

 known great speed of this powerful current. In Note 1 of the 

 Appendix the data are discussed; and it is shown that whilst in 

 the slacker water in the vicinity of St. Paul's Rocks and Ascension, 

 that is, in the northern and southern portions of the current, the 

 bottles are carried along at a rate of about twenty miles a day, in 

 the centre of the stream, as it concentrates between St. Paul's Rocks 

 and Cape St. Roque, an average speed of thirty miles is attained. 

 From what has been said it would be expected that during the 

 remainder of the passage along the South American seaboard to 

 the West Indian region the speed of bottle-drift would respond to the 

 increase in the velocity of the current as it sweeps past the coasts 

 of North Brazil and the Guianas. This expectation is fully justified 

 in the facts given in the note, where a daily rate of between thirty 

 and fifty miles, and averaging forty miles, is indicated. It may be 

 inferred from these data that, starting from the Gulf of Guinea, a 

 bottle would require an average period of twelve weeks to reach 

 the vicinity of Cape St. Roque and of seventeen weeks to reach 

 Trinidad. It is, however, not improbable when the current runs 

 with unusually great speed that the traverse to the Brazilian coast 

 may be performed in as little as two months. 



The Drifting Rate of Bottles from off the Amazon Estuary 

 to the Coast of Florida. — This establishes an interesting connec- 

 tion, since we already know how long a period is usually required 

 by bottle-drift for the passage from Florida to the shores of Europe, 

 namely, fourteen months; and we shall thus be able to determine 

 the time that would be required for Amazon drift, as typified by the 

 floating bottle, to reach our coasts. As previously remarked, the 

 track assigned in both the American and German charts to bottles 

 that arrive in the Florida seas from latitudes in the tropical Atlantic 

 south of 10° N. lies across the Caribbean Sea and through the Straits 

 of Yucatan. The data for three bottles that accomplished this 

 passage from off the Amazon to Florida waters are supplied in 

 Note 1 of the Appendix. It is there inferred that this traverse 

 of 3200 miles would be performed in about six months at the rate 

 of seventeen miles a day, from which it may be concluded that as 

 a rule the passage of Amazon drift to Europe would occupy twenty 

 months. 



The Drift-Rates in the Brazil Current. — The Brazil Current 

 has been before alluded to as an extension of the South Equatorial 

 Current. Its velocity is usually stated to be from twelve to twenty 



