EXPLANATION OF OCEAN TEMPERATURE CHART No. 17. 



VINEYARD SOUND LIGHT-SHIP, MASSACHUSETTS. 

 Observers : William H. Doane, A. H. Bray. 



Location of station. — The Vineyard Sound, or " Sow and Pigs'' light-ship, as it was formerly called, is anchored 1 

 mile to the south west ward of Sow and Pigs Eeef, and 2| miles S W. by W. of the light on Cuttyhuuk Island, the sonth- 

 ernmost of the Elizabeth Group. It is situated 17^ miles E. by S. J S. of Brenton's Eeef light-ship, and on the western 

 side of the southern entrance to Vineyard Sound. Within a radius of a mile the depths range from 4J to 164 fathoms. 

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



Geographical position.— JjatituAe, 41° 23' (02") N. ; longitude, 70° 59' (01") W. 



Depth of water. — Fifteen fathoms. 



Eange of temperature (March 1 to January 1).— Air, 43° (28°.5 to 710.5) ; surface, 37° (31° to 68°). 



The temperatures for the colder months were evidently more carefully read 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 ihe winds, iij quadrants, for each month of the year, being the means of five years' observations. 



•208 



