S58 Dr Marcef s Experiments on Sea- Water. 
From the preceding facts Dr Marcet concludes, 
1. That the Southern Ocean contains more salt than the 
Northern Ocean, in the ratio of 1.02919 to 1.02757. 
2. That the mean specific gravity of sea-water near the Equa- 
tor is 1.02777, intermediate between that of the Northern and 
Southern Hemispheres. 
3. That there is no notable difference in sea-water under dif- 
ferent meridians. 
4. That there is no satisfactory evidence, that the sea at great 
depths is more salt than at the surface 
5. That the sea, in general, contains more salt where it is 
deepest, and most remote from land, and that its saltness is al- 
ways diminished in the vicinity of large masses of ice. 
6. That small inland seas, though communicating with the 
ocean, are much less salt than the open ocean. 
'7. The Mediterranean contains rather larger proportions of 
salt than the ocean. 
The singularity of this last result has been explained, upon 
the supposition that the Mediterranean Is not supplied by the 
rivers which flow into it, with a quantity of fresh water suffi- 
. cient to replace what it loses by evaporation under a burning 
sun, aided by a powerful radiation from the African shores, and 
the parching winds blowing from the adjacent desarts. Philo- 
sophers have, therefore, attempted to explain why this sea does 
not gradually increase in saltness, and indeed be ultimately 
converted into saturated brine. This has been ascribed to an 
under current of water, salter than the ocean, which runs out at 
the Straits of Gibraltar, and unloads its waters of their excess of 
salt.- This idea of a submarine current is countenanced by the 
fact, communicated to Dr Marcet by Dr Macmichael, on the 
authority of the British Consul at Valentia, that some years 
* A similar conclusion was deduced by Mr Scoresby, who obtained the fol- 
lowing results. See his Account of the Arctic Regions. 
Depth in 
F eet. 
Lat. 
76^ 16' ) 
Surface 
738 
1380 
Spec. 
Grav. 
1.0261 
1.0270 
1.0269 
Depth in 
Spec. 
Spec. 
Feet. 
Grav. 
Depth in 
r Surface 
1.0265 
Feet. 
Grav. 
120 
1.0264 
Lat. 
77“ 40' 
( Surface 
1.0261 
\ 210 
1.0266 
J 300 
1.0265 
360 
L 600 
1.0268 
1,0267 
( 660 
1.0262 
