of the North Atlantic and Northern Oceans* 115 



the mean atmospheric and oceanic temperatures : and where 

 they may seem to indicate the region from which peculiar 

 qualities of the sea are derived, they can afford but little, if 

 any, information as to the precise direction or strength of the 

 current so indicated, yet still the general results are found 

 important and useful. The researches of the author embrace 

 those in the Greenland Sea, the North Sea, and a consider- 

 able belt across the North Atlantic. To those in the North 

 Atlantic he wished at present to direct attention ; and to a 

 belt of it embraced within the limits of a series of passages 

 chiefly by sailing vessels between England, or some European 

 port, and New York. Of these passages, sixteen in number, 

 four were performed by the author himself, and twelve were 

 supplied by an American navigator, Capt. J. C. Delano, an 

 accurate scientific observer. The observations on surface 

 temperature discussed amount to 1153, gathered from a total 

 number of about 1400. Usually Capt. Delano recorded six 

 observations each day during the voyage, at intervals of four 

 hours. Seven of the passages were made in the spring of 

 the year, — two in the summer, — one in autumn, — and three 

 in winter. Taking the middle day of each passage the mean 

 day at sea was found to be May 18th or 19th, — a day fortu- 

 nately coincident in singular nearness with the probable time 

 of the mean annual oceanic temperature. The author had 

 laid down the tracks of the ship in each of the voyages on a 

 chart of Mercator's projection, and the principal observations 

 on surface temperature were marked in their respective places. 

 The observations were then tabulated for meridians of 2° in 

 breadth, from Cape Clear, longitude 10° W., to the eastern 

 point of Long Island, longitude 72° W.., — embracing a belt 

 of the average breadth of 220 miles, or a stretch of about 2600 

 miles across the Atlantic. The results were the following : 

 — 1. Highest surface temperature northward of latitude 40°, 

 74° ; lowest 32° ; range 39° : 2. Mean surface temperature 

 as derived from the means of each meridional section, 56°, 

 whilst the mean atmospheric temperature for the correspond- 

 ing period was 54°-2 : 3. Range of surface temperature 

 within each meridional section of 2°, 8J-° at the lowest, being 

 in longitude 20-22° W., and at the greatest 36°, being within 



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