EXPLANATION OF OCEAN TEMPERATURE CHART No. 21. 



BOON ISLAND LIGHT-HOUSE, MAINE. 



Ohserver: Alfkeu J. Le.witt. 



Location of station. — Boou IsUiuit is ;i .sin;in, low, rockj' islaud, ofl' York Harbor, Maine, and 5i miles (Vom Cajje 

 Neddick, tLe nearest part of the maiulaud. From Thatcher's Island it is distaut about 35 miles, in a northerly direc- 

 tion. Within a radius of 1 mile depths of 5^ to 25 fathoms occur, and a depth of 60 fathoms is reached at a distance 

 of about 6i miles to the eastward and southeastward. 



Geographical position of the lighthouse. — L.atitude, 43° 07' 17" N. ; lon<;itudo, 70° 28' 37" W. 



Depth of water. — Nine fathoms. 



Hange of temperature (March 1 to ,J,uiu:uy 1).— Air, 51° (Sio.S to 73°.5) ; surface, 29° (33° to C2°). 



This staticm affords the highest maximum surface temperature of any of the stations located in the uorlhcrn part 

 of the Gulf of Maine. This maximum is 5° lower than at Thatcher's Island, hut agrees exactly wilhthe surface maxi- 

 nuims at Pollock Rip and Nantucket New South Shoal. The maximum for the air is, however, somewhat hij;her at 

 Boou Islaud than at the two light-ships mentioned. The surface curves are more irregular than at the other stations 

 in the Gulf of Maine. It is necessary to explain, however, that the surface observations were not taken with any regu- 

 larity at this station, omissions of several days, sometimes as many as five or sis days, occurring in a majority of the 

 ten-day periods. The omissions are much less frequent during the summer than the winter months. It is impossible 

 to calculate to what extent the results may bo vitiated by this fact. 



Tul)le showing the direction of the winds, hij quadrants, for each mj«(A of the year, being the means of five i/ears' observations. 



Quu'lr^ut. 



Noriheast . . . 



Southeast 



SoQthwcst 



Xorthwcat 



.Jiinuarj'. 



3.2 

 9 

 10.9 



Febru- 

 ary. 



3.0 

 7.2 

 6.4 



March, 



9.3 

 .1.0 

 5.5 

 10.5 



April. 



9.1 

 8.8 

 3.9 

 8 



May. 



9.9 

 13 

 4.5 

 3.2 



Juno. 



5.3 



13.3 

 5.0 

 4.8 



July. 



5.8 

 I-.' 

 7.7 

 3.8 



7.5 

 10 

 10.5 



2.6 



Septem- 

 Ik r. 



10 

 10.1 







3.1 



October. 



11.4 

 7.3 

 7.7 

 4.2 



Novem- 

 ber. 



9.7 

 4.3 

 9.1 

 6.8 



Decem- 

 ber. 



8.8 

 4 



U.O 

 8.» 



216 



