EXPLANATION OF OCEAN TEMPERATURE CHART No. 6. 



RATTLESNAKE SHOAL LIGHT-SHIP, SOUTH CAROLINA. 



Observer : JouN McCoRiiiCK. 



Position. — Rattlesnake Shoal light-ship is placed just north of the entrance to Charleston Harbor, South Carolina, 

 and about 56 miles northeasterly from Martin's Industry light-.ship. It is anchored about 5 miles off shore, and 2 

 miles off the shoals of the same name, between which and the light-ship there are depths of 4 to 5 fathoms. The 

 10-fath)ra curve is distaut about 11 miles, the 20-fathom curve about 30 miles, and the 100-fathom curve about 50 

 miles. 



Gtograpliicalposilion.— Ijalitude, 32° 44' (00") N. ; longitude, 79^ 43' (40") W. 



Depth oftcatcr. — Five fathoms. 



nange of temperature— Air, 41° (45°.5 to 86°.5) ; surface, 38° (47° to 85°). 



The range of temperature at this station is almost precisely the same as at Martin's ludnstry, there being a dif- 

 ference of only half a degree in the air records. The curves as plotted also agree closely at the two stations, both 

 as regards their general features and their details. 



Tahle allowing the direction of the loiiuls, hij quadrants, for each month of the gear, hcing the means of fire gears' observations. 



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