220 
PEOFESSOE FOECHHAMMEE ON THE COMPOSITION 
water. The following remarks, and the Tables which belong to them, will show that 
there is a very small difference in the coefficient of the different parts of the ocean, but 
that the differences become striking in the neighbourhood of the shores. 
A. On the salinity of the surface of the different 'parts of the ocean and its inlets. 
In the Tables annexed to this paper I have divided the sea into seventeen regions. 
My reason for doing so was that by this method I was able to avoid the prevailing 
influence which those parts of the ocean which are best known, and from which I have 
most observations, would exert upon the calculations of the mean number for the whole 
ocean. 
First Region. The Atlantic Ocean between the Equator and 30° N. lat. — The mean of 
fourteen complete analyses is 36T69 per 1000 salt; the maximum is 37*908 per 1000, 
the minimum 34*283. The maximum lies in 24° 13' N. lat. and 23° 11' W. long., 
about 5° W. from the coast of Africa, where no rivers of any size carry water from the 
land, and where the influence of the dry and hot winds of the Sahara is prevailing. 
The maximum for the region is also the maximum of surface-water for the whole 
Atlantic ; it is equal to the mean salinity of the Mediterranean, and only the maximum 
of that sea off the Libyan desert and that of the Red Sea are higher. The minimum 
is from 4° 10' S. lat. and 5° 36' W. long, close to the coast of Africa, where the large 
masses of fresh water which the great rivers of that region pour into the ocean exercise 
their influence. Its coefficient is 1*810. 
Second Region. The Atlantic Ocean between 30° N. lad. and a line from the north point 
of Scotland to the north point of Newfoundland. — The mean of twenty-four complete 
analyses is 35*946 salt, the maximum 36*927, and the minimum 33*854. The maximum 
is in 38° 18' N. lat. and 43° 14' W. long, in the middle of the Atlantic; the minimum 
occurs in 43° 26' N. lat. and 44° 19' W. long., and is evidently owing to the enormous 
quantity of fresh water which the St. Lawrence, through its southern mouth, pours into 
the Atlantic. This region is under the influence of the Gulf-stream, and the corre- 
sponding South Atlantic region has only a mean salinity of 35*038. Its coefficient is 
1*812. 
Third Region. The northern part of the Atlantic , between the northern boundary of the 
second region , and a line from the south-west cape of Iceland to Sandwich Bay in 
Labrador. — The mean salinity deduced from twelve complete analyses is 35*391, its 
maximum 36*480, its minimum 34*831. The maximum falls in 55° 45' N. lat. and 
20° 30' W. long., just on the boundary of Region 2, the minimum in 60° 25' N. lat. 
and 3° 15' W. long., near the large northerly opening of the North Sea. This region 
owes evidently its high salinity to the large northern direct branch of the Gulf-stream. 
Its coefficient is 1*808. 
Fourth Region. This region comprehends the East Greenland current , which flows 
along the east coast of Greenland towards the south and west , turns towards the north , 
when it reaches the south promontory of Greenland , runs along the west coast of that 
large land into Davis Straits , where it disappears in the polar current from Baffin's Bay. 
