30 
DR. WOLLASTON ON THE WATER OF THE MEDITERRANEAN. 
other persons with portions of his collection, which were afterwards applied 
by them to other objects. 
Nevertheless, at the time when I had the good fortune to be introduced to 
Captain Smith, in the month of June 1827, he still retained in his possession 
three bottles, the remainder of his stock, and at my request most obligingly 
sent them to me for examination. 
Happily, one of these is such as to accord in the most complete manner 
with the anticipation, that an accumulation of denser water might be found at 
great depths in the neighbourhood of the Straits, from which a counter- 
current beneath, though far less rapid, might carry westward into the Atlantic, 
as much salt as enters, with the eastward current near the surface, from that 
ocean into the Mediterranean. 
The evidence of this will be comprised, indeed, in very few words : for 
though the two first specimens, taken at distances of about 680 and 450 miles 
from the Straits, and at depths of 450 and 400 fathoms respectively, do not 
exceed in density that of many ordinary samples of sea-water, yet the last, 
which was taken up at about 50 miles within the Straits, and from a depth of 
6/0 fathoms, has a density exceeding that of distilled water by more than four 
times the usual excess, and accordingly leaves upon evaporation more than 
four times the usual quantity of saline residuum. 
Hence it is clear, that an under-current outward of such denser water, if of 
equal breadth and depth with the current inward near the surface, would carry 
out as much salt below as is brought in above, although it moved with less 
than ^th part of the velocity, and would thus prevent a perpetual increase of 
saltness in the Mediterranean Sea beyond that existing in the Atlantic. 
On comparison of the relative specific gravities and quantities of salt, in 
the Table subjoined to this paper, with those in Dr. Marcet’s Table, there may 
be remarked a want of accordance between the two experimenters, that will 
require to be explained. 
This difference arises from the different temperatures at which his results 
and mine were dried. In his experiments the degree of heat chosen was 212° ; 
in mine, the temperature was raised beyond 300°. In each case it will be seen 
that the quantity of saline contents to be obtained may be estimated from the 
specific gravity, by multiplying the excess of density above that of distilled 
