THE GULF STEEAM. 409 



corresponding to the first temperature was about 3T^ 20', and to the last 

 about 28° 20'. Lieutenant Charles H. Davis, in October, 1845, found a 

 temperature of 40° at 1,000 fathoms, in lat. 39° 25', long. 69° 1', and 

 Lieutenant George M. Bache 40° at 2,160 fathoms, in lat. 34° 13', long. 

 68° 5'. Lieutenant S. P. Lee, in August, 1847, found 37° below the Gulf 

 Stream, at the depth of 1,000 fathoms, in lat. 35° 26', long. 73° 12' ; and 

 again 48° beyond the Gulf Stream, at the same depth, in lat. 30° 10', long. 

 68° 9'. Lieutenant Eichard Bache, in July, 1848, found a temperature of 

 42° at 1,000 fathoms, in lat. 35° 6', long. 74° 7', below the surface of the 

 Gulf Stream. 



" The fact that the side limits of the Polar Current recede from the shore 

 as the depth increases, is clearly marked on all the sections. Directly down 

 below the maximum surface temperature, we soon plunge into this cold 

 current, the warmer water receding from the shore, and at 400 fathoms 

 reach temperatures, the differences between which, at the North and South, 

 are of an order corresponding to the variations of the ocean waters in 

 different years and at different seasons. For example, at the depth of 400 

 fathoms, on the Sandy Hook section, in 1846, vertically below the crest of 

 the Gulf Stream the temperature was 51° F. ; on the Henlopen section, at 

 the corresponding point, 51° ; on the Cape Henry section, 54|-° ; in 1848, 

 on the Cape Henry section, 52^° ; and on the Hatteras section, 52° ; in 

 1853, on the Hatteras section, 51° ; and on the Cape Fear section, 54° ; all 

 the foregoing observations being made in July and August of the several 

 years. In June, 1853, the temperature at the point and depth before noted 

 on the Charleston section, was 55°, and near Cape Florida, 14 miles E.N.E. 

 from the light, was 51°, varying from 54° to 46° in the intermediate localities 

 The low temperature of 46° was observed on the Canaveral section. The 

 temperature at 400 fathoms, near Cape Florida, is the same as observed on 

 the Sandy Hook section in July, 1846, viz., 49°. 



" I remarked that these differences came within the annual changes neat 

 the surface. Not to complicate the examination with surface irregularities, 

 if we compare the maximum temperatures at 12 or 15 fathoms below the 

 surface of the different sections, in the same year, we shall find, as a general 

 rule, an increase of temperature in passing Southward, as 81°, 83°, 82°, 

 from the Sandy Hook to the Cape Henry section ; in 1846, 75|°, 76°, 77^°, 

 79^°, from the Charleston section to that of Cape Canaveral. But in succes- 

 sive years we have for the highest temperature at 12 fathoms, on the Cape 

 Henry section, higher than that of Hatteras ; and the temperature in July, 

 1846, on the axis of the Gulf Stream, higher at Sandy Hook than in June, 

 1853, at Canaveral, by 1^°, and higher than Charleston by 5^°. It ia 

 obvious that here an interesting field of enquiry opens, requiring careful 

 research." 



(399.) Counter-Currents. — Besides the great Arctic Current which flows 

 Southward inside the Gulf Stream, and to be described in the next Section, 

 there are some other counter-currents on each side of the Stream which 

 require notice here. They appear in the first part of its course in the Gulf 

 of Florida, where they have been known to flow from the earliest times, and 

 alluded to in (374), page 388. 



N, A. 0. 53 



