THE GULF STREAM. 



399 



accepted idea, that the warmer the water the stronger the current from 

 the South. 



The following Table gives the position of the Axis of the Stream , where 

 the greatest Velocity may be found, on the third day after the moon's 

 highest and after zero declination. 



Passing through the Straits of Florida, the axis of the Stream off Havana 

 is nearest the Southern edge, but after making the bend between Salt Kay 

 and Florida Reefs the axis is from 4^ to 11^ miles outside the lOO-fathoms 

 line on the West side. From Jupiter Inlet to Hatteras the average posi- 

 tion of the axis is probably from 11 to 20 miles outside the lOO-fathoms 

 line. 



The data obtained off Hatteras are not sufficient to decide positively how 

 much the movement of the axis is. The width of the Stream at high 

 declination is about 40 miles, reckoning from the lOO-fathoms line, which 

 is about the same width as in the narrowest parts of the Straits of Florida. 

 It is probable that at high declination the position of the axis at Cape 

 Hatteras is not more than 12 or 15 miles farther off shore than the mean 

 position, but the conditions of the current outside the Stream at this point 

 cause a slow surface-flow at times, which may lead to the belief that the 

 Stream itself is very broad. 



Daily Variatmi. — When the flow of the Stream is in the vicinity of the 

 land, there is a marked daily variation in the velocity, caused by the ele- 

 vation or depression due to the attraction of the moon and sun. There is 

 a retardation of about 3 hours in the effect produced by this tidal influence. 

 More exactly, the maximum Current near Tobago and St. Lucia occurs 

 €*" 10™ after the moon's transit ; in the Yucatan Passage, about 2'' 26"" ; 

 in the Straits of Florida, off Havana, 3'' 4"" ; off Cape Florida, 3'^ 26"'. In 

 the open sea the daily variation is not marked. 



In the vicinity of Barbadoes the time of high water is about 3 hours 

 after the transit of the moon, giving a retardation of S^ 10™ in the maximum 

 flow. The maximum in the Straits of Florida is the reverse of that of the 

 Equatorial Current, its arrival being 2^ 15™ after mean low water at the 

 Southern Atlantic ports of the United States. 



In the Straits of Florida, off Cape Florida, there is but one prominent 

 maximum daily variation of velocity, usually arriving 9 hours before the 

 upper transit of the moon. South of Rebecca Shoal Lighthouse, at a 

 distance of 20 miles, the mean surface velocity is 0-30 knot, with a 

 maximum daily variation of 0-62 (giving at times a Westerly current of 

 032 knot) and a mean daily variation of 0-49 ; at 35 miles, 0-74, 1-15, 

 and 0-77 ; at 50 miles, 2-24, 0-65, and 0-62 ; at 68 miles, 2-23, 0-80, an] 



