EXPLANATION OF OCEAN TEMPERATURE CHART No. 15. 



BLOCK ISLAND SOUTHEAST LIGHT-HOTJSE, EHODE ISLAND. 



Observer: H. W. Clark. 



■ Location of station. — Tliis light-house is located on the high bluff at the southeastern extremity of Block Island, 

 and is distant 83 miles northeasterly from Fire Island Light-house, and 78i miles W. by N. f N. from Nantucket New 

 South Shoal light-ship. The water is very shallow off the southern end of the island, the depths increasing gradually 

 seaward. The SO'fathom curve is distant about 5 miles ; the 100-fathom curve, about 70 miles. 



Geographical posilion.—'Latitndia, 41° 09' 10" N., longitude, 71° 33' 09" W. 



Depth of water. — The observations were taken at the edge of the beach, helow the light-house, facing the open sea 

 to the south. 



Bange of temperature (March 1 to January 1).— Air, 57° (22° to 79°); surface, 41° (29o:5 to 70°.5). 



Although the observations were taken from the beach, the surface curves show little direct influence of the air 

 temperature upon the water, and are comparatively regular. The maximum air temperature is ahout the same as at 

 Absecon, N. J., but the maximum for the surface is four degrees lower than at any of the stations to the west and 

 south. 



Table shoioing the direction of the winds, hy quadrants, for eajih month of the year, being the means of five years' observations. 



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