EXPLANATION OF OCEAN TEMPERATURE CHART No. 17. 



VINEYARD SOUND LIGHT-SHIP, MASSACHUSETTS. 

 Observers: Willi.\.m H. Doajje, A. H. Br.\y. 



Location of atalion. — The Vineyard Sound, or " Sow and Pigs" ligbt-sbij), a.s it was formerly called, is anchored 1 

 mile to the south westward of Sow and Pigs Reef, and 2i miles S\V. by W. of the light on Cuttyhuuk Island, the sonth- 

 ernmost of the Elizabeth Group. It is situated 1"| miles E. by S. J S. of Brenton's Reef light-ship, and on the western 

 side of the southern entrance to Vineyard Sound. Within a radius of a mile the depths range from 4^ to RU fathoms. 

 The 20-fathom curve is distant about C miles; the 100-fathom curve, about 80 miles. 



GeoaraphicalposUion.—ljAiW-aaQ, 41° 23' (02") N. ; longitude, 70° 59' (01") W. 



Depth of water.— Fii'teeu fathoms. 



Emige of temperature (March 1 to January 1).— Air, 43° (28°. 5 to 71°. 5) ; surface, 37° (31° to 08°). 



The temperatures for the colder mouths were evidently more carefully road here than at most of the northern 

 stations, and the curves have been plotted on the chart for the entire year. In reckoning the ranges of temperature, 

 however, January and February have been omitted to facilitate comparisons with the neighboring stations. Com- 

 pared with Brenton's Eeef, the maximum air record is 3° lower, the maximum surface only 1° lower, indicating 

 closely corresponding conditions. 



Tahle showing the direction, of the winils, hi/ quadrants, for each month of the year, being the means of fire years' obscrrationK. 



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