EXPLANATION OF OCEAN TEMPERATURE CHART No. 16. 



BRENTON'S KEEF LIGHT-SHIP, RHODE ISLAND. 

 Observer : Charles D. Marsh. 



Location of station.— This ligbt-sliip is located iu the middle of the entrance to Narragausett Bay, about Ij milca 

 SW. of the southern point of the Island of Rhode Island, and a little over a mile ofi' Brenton's Reef, the depths 

 between ranging from 4| to l-lf fathoms. It is 17f miles NE. | N. of Block Island southeast light, and faces the 

 open sea to the south, the depths increasing gradually seaward. The 20-fathom curve is distant about 8| miles ; the 

 100-fathom curve, about 85 miles. 



GeograpUcalposilion.—l^s.i\to.Ae,, 41° 25' (52") N. ; longitude, 71° 22' (3G") W. 



Depth of xnater. — Fourteen and one-half fathoms. 



lianije of temperature (March 1 to January 1). — Air, 45<^.5 (29° to 74°. 5); surface, 35° (34° to G9°). 



The minimum temperatures are higher, the maximum lower at this station than at Block Island. The maximum 

 surface temperatures, however, show a difference of only 1^° for the two stations. It is probJible that the surtace 

 observations for Brenton's Reef are the more reliable, having been t.aken where the water is 14^ fathoms deep. 



Table showing the direction of the loinds, bij quadrants, for each month of the year, being the means of five years' observations. 



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