162 FISHIKG-GEOUNDS OF NORTH AMEEICA. 



ENUMBEATION AND BRIEF DESCRIPTIONS OF THE STATIONS. 



The light houses and light-ships selected as temperature stations numbered thirty-six in all, 

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

 Eastern Maine, to the Tortugas Eeefs 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, in 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 Oape 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 bo made. 



The outside stations differ widely in 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 light-ships, authored 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 influences, 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 ranges of temperature in succes- 

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



THE FLORIDA EEEFS. 



Dry lorlugas UgM-hoiise. — Located ou the western island of the Tortugas, at the southwestern extremity of the 

 Florida Keefs. 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 ^nd occupied by strong tidal currents. The surface temperature observan 

 tloas were taken whore the water is oaly 5 feet deep, and show indications of local influences, which render them 

 more or less unsatisfactory with respect to the open waters sarrounding the reefs. 



Cartjsfort Beef light-house. — Located near the northeastern end of the Florida Eeefs, about 158 miles from the 

 Dry Tortugas light-house, and on the outer side of Carysfort Eeef. Depths of 50 fathoms occur within 2 miles of 

 the light. Observations were taken in a dep.th of only 3 feet, but evidently in a more exposed position than at the 

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



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

 Eeefs, and 23 miles from Carysfort Eeef. The 100-fathom curve Is distant about 2i miles. The depth of water at the 

 place of observation is 5 feet, and the water temperature records compare favorably with those of Carysfort Eeef, 

 indicating a similar exposure. . 



SOUTH CAROLINA. 



Martin's Industry light-ship. — Anchored in 9 fathoms of water, about 8^ miles from land, off the entrance to Port 

 Eoyal Sound ; distant about 390 miles from Fowey Eocks light-house. 



Battlesndke Shoal lightship. — Anchored in 5 fathoms of water, about 5 miles off land, just nordi of the entrance 

 to Charleston Harbor, and about 56 miles from Martin's Industry light-ship. 



NORTH CAROLINA. 



Frying Pan Shoals light-ship.— Auchoved in 10 fathoms of water, about 17 miles southeast of Cape Fear, and 

 about 108 miles from Eattlesnake 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, and attains a depth of 10 fathoms about 5 miles from shore. Although 

 the maximum and minimum surface temperatures at this station correspond closely with the same at Frying Pan 

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



* For more complete descriptions, reference should be made to the explanations of the charts. 



