EXPLANATION OF OCEAN TEMPERATURE CHART No. 4. 



FOWEY ROCKS LIGHT-HOUSE, FLORIDA. 

 Observer: John J. Larxer. 



Position. — Fowcy Rocks light-Louse is built ou Fowey Rocks, whicli are located very near tbe northeastern 

 extremity of the Florida Reefs, about 6 miles southeasterly from Cape Florida, aud 23 miles northerly from Carysfort 

 Reef. These rocks are on the western side of the Straits of Florida, in their northern and narrowest portion, some- 

 times called the Straits of Bernini, the eastern border of which is formed by the northwestern extremity of the Great 

 Bahama Bank. Tbe light-house is situated on the outer edge of the rocks, which lie directly in front of the widest 

 opening to Key Biscayne Bay. Depths of 7 to 16 fathoms occur close to the light ; the ICO-fathom line is distant only 

 about 2J miles, and the axis of the Gulf Stream about 24 miles. 



r;eo(/)-aiJ/iicaZj)osi7ioH.— Latitude, 25° 35' 25" N. ; longitude, 80° O.V 41" W. 



J)ei>ih ofuatcr. — Five feet. 



Hatigc oficmjjerature.— Ah; 18° (08° to 86°) ; surface, 10°.5 (70° to SG°.5). 



There is comparatively little difference between the temperatures at Fowey Rocks aud Carysfort Reef, these two 

 stations, located only 23 miles ajiart, being more closely related than are either of them to the Tortugas. The air 

 tcmi)eratures range slightly higher at this station than at Carysfort, but the surface curves correspond very closely 

 throughout each year, tbe greatest dilferenco at any period being only 2° or 3°. Tbe more prominent irregularities 

 in the surface curves at one station are almost invariably repeated in those of the other at the same period. The angles 

 indicating low temperatures for March, 1881, are more pronounced here than at Carysfort, but those for the last jiart 

 of 1832 are less marked. Tbe maximum air and surface temperatures at this station are very nearly identical. 



Table showing the direction of the winds, bij quadrants, /•,r each month of the year, being the means of fire gears' obserrations. 



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