102 FISHING-GKOUNDS OF NORTH AMEEICA. 



ENUMERATION AND BRIEK DESCRIPTIONS OF THE STATIONS. 



The light houses and lightships selected as temi)eratnre stations numbered thirty-six iu all, 

 distributed at intervals along the eastern coast of the United States, from Petit Manan Island iu 

 Eastern Maine, to the Tortugas Reefs in Southern Florida. As explained before, twenty-six of these 

 stations were located off shore, or on exposed portions of the coast, and the remainder in more or 

 less inclosed bays, sounds, and harbors. The outside stations are alone considered in this report, 

 and of this class the two following have been omitted, reducing the number to twenty-four. The 

 observations were continued for so short a period at Minot's Ledge light-house, iu Massachusetts 

 Bay, that it was deemed inexpedient to make use of them ; and the records for Race Point light- 

 house, at the northern extremity of Cape Cod, show such extreme variations within short periods, 

 due probably in part to the very gradually sloping shore in front of the light, as to render their 

 value questionable until further examination can be made. 



The outside stations differ widely iu the character of their surroundings, and therefore do not 

 afford the means of obtaining observations of equal value respecting the open waters along the 

 coast. Ten are lightships, anchored off' shore, in depths of 5 to 18 fathoms, and consequently pos- 

 sessing unusual advantages for the taking of ocean temperatures ; nine are located on small islands 

 or reefs, more or less widely separated from the mainland ; and five are situated on the shore of 

 the mainland or on large islands, the last, as a rule, forming the least desirable stations of the 

 series. Some of those stations situated on small islands or reefs also show considerable variations 

 of temperature due to local iufluences, as described further on. 



The arrangement of stations followed in this report is generally from south to north, this order 

 affording the most natural sequence for comparing the different rauges of temperature in succes- 

 sive latitudes. The locations and general characteristics of the stations are as follows : * 



THE FLORIDA REEFS. 



Dry Tortugas Vyht-house. — Located ou tbe western island of the Tortugas, at the southwestern extremity of the 

 Florida Reefs. The light-house is situated ou the eastern side of Loggerhead Key (or island), which is bordered by a 

 channel having depths of 10 to 12 fathoms and occupied by strong tidal currents. The surface temperature observa- 

 tions were taken where the water is only 5 feet deep, and show indications of local influences, which render them 

 more or less unsatisfiictory with respect to the open waters surrounding the reefs. 



Carijsfort Eeef light-house. — Located near the uortheastern end of the Florida Reefs, about 158 miles from the 

 Dry Tortugas light-house, and ou the outer side of Carysfort Reef. Depths of GO fathoms occur within 2 miles of 

 the light. Observations were taken in a depth of only 3 feet, but evidently in a more exposed positiou than at the 

 Tortugas station, as the effects of local influences are less apparent in the surface temperature records. 



Fowey liocka light-house. — Located on the outer edge of Fowey Rocks, at the northeastern extremity of the Florida 

 Reefs, and 23 miles from Carysfort Reef. The 100-fathom curve is distant about '2i miles. The depth of water at tbe 

 place of observation is 5 feet, and tbe water temperature records compare favorably witli those of Carysfort Reef, 

 indicating a similar exposure. 



SOUTH CAUOLINA. 



Martiii's Industry light-shij). — Anchored in 9 fathoms of water, about 84 miles from land, off the entrance to Port 

 Royal Sound ; distant about 390 miles from Fowey Rocks light-house. 



Hattleanakc Shoal light-ship. — Anchored in 5 fathoms of water, about 5 miles off land, just north of the entrance 

 to Charleston Harbor, and aViout 50 miles from Martin's Industry light-ship. 



NORTH CAROLINA. 



Frying Pan Shoals /iV//i/-.v/ii/).— Anchored iu 10 fathoms of water, al)oul 17 miles southeast of Capo Fear, and 

 about 108 miles from Rattlesnake Shoal light-ship. 



Cape Lookout light-house. — Located on the outer shore, about 3 miles north of the extremity of Cape Lookout, and 

 90 miles from Frying Pan .Shoals light-ship. The observations were taken at the lower edge of the beach in a depth 

 of 1 foot of water. The bottom slopes gradually, aud attains a depth of 10 fat horns about ,'j miles from shore. Although 

 the maximum and minimnm surface temperatures at tliis station correspond closely with the same at Frying Pan 

 Shoals, the surface curves are much less regular, aud show direct atmospheric influence. 



* For more complete descriptions, reference should 1)0 made to the explanations of the chart.s. 



