174 &r. Marcet on the specific gravity, and temperature 
hereafter be explained, and appear independent of any ge- 
neral law. 
In general the waters of the ocean, whether taken from 
the bottom or from the surface, appear to contain most salt in 
places in which the sea is deepest or most remote from land ; 
and the vicinity of large masses of ice seems to have a si- 
milar effect to that of land in diminishing the saltness of the 
sea. If, therefore, in attempting to approach the Pole, the 
saltness of the sea should appear to increase, and become 
more uniform at the surface, such a circumstance might be 
considered as militating against the probability of the sea 
being extensively frozen in those regions. 
It may be stated generally, that small inland seas, though 
communicating with the ocean, are much less salt than the 
open ocean. This is particularly striking in the case of the 
Baltic ; and also, though in a less remarkable degree, in the 
Black sea, in the White sea, in the sea of Marmora, and even 
in the Yellow sea.* 
The Mediterranean, though a comparatively small and 
subordinate sea, is found to contain rather a larger proportion 
of salt than the ocean.-f This appears to form an exception 
* The Caspian sea is also said, but upon no certain authority, to be less salt 
than the ocean. Its waters having, like those of the Dead sea, no obvious communi- 
cation with those of any other seas, present a particular case well deserving of 
investigation ; and I regret that I have not yet been able to procure a specimen 
of them, notwithstanding the various attempts which I have made for that purpose. 
f This has been stated by various writers, and appears to be the case from the 
few specimens which I have examined ; but I cannot speak with perlect confidence 
on this point, as I was but scantily supplied with water from that sea, though 
comparatively so near and so much frequented by navigators of all descriptions. In 
their analysis of sea water, Bouillon-La Grange, and Vogel state the propor- 
tion of saline matter in the water of the Mediterranean to be 41, that of the Atlantic 
being 38, and that of the English Channel 36. 
