258 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
outside influences of any kind must be least active, is further evidence 3 
that it is winter cooling by the air that is responsible in the main for 
the cold water. And this same process equally well explains the gen- _ 
eral persistence of low temperature in summer near shore below — 
twenty fathoms or so, solar warming progressing but slowly below | 
that depth, consequent on the progressive increase in the vertical 
stability of the water. 
And how closely mean air and water temperatures agree, for 
bays and sounds, is illustrated by Long Island Sound, where the 
mean surface temperature for the year (52°-53°) is practically the 
same as the mean air temperature for the year at New York. The 
mean surface temperature in Massachusetts Bay is about 50°-52°; 
the mean air temperature at Boston about 4.9°. In short, the tem- 
perature of the coast water between Cape Sable and Chesapeake Bay 
is not abnormally low, considering its relation to the land mass to the 
west, and the winter climate of the latter. Hence it gives no direct 
support to the upwelling theory. 
Neither is there anything in the surface temperature curves to 
suggest such upwellings as those off California, off Morocco, and off 
South Africa, for though the surface temperature is much lower over 
some of the coast banks, and in the northeast corner of the Gulf of 
Maine as a whole, than elsewhere, subsurface temperatures, salinities, 
and tidal currents prove that their cold surface is the result of violent 
vertical circulation, accompanied by correspondingly high bottom 
temperatures. Furthermore, the mean temperature is lowest where 
there seems to be the least possibility of abyssal upwelling, 2. e., in 
partially enclosed basins next the coast. 
The rapid rise of surface temperature during July and August is in 
itself a strong argument against the view that upwelling can have been 
active at that time; and so is the great annual range of surface temper- 
ature (30° for the Gulf of Maine, nearly 40° off New York, with an 
even greater extreme range, Murray, 1898); for any considerable up- 
welling of cold abyssal water would necessarily check the former, and 
consequently lessen the latter. It would be hard to reconcile our sub- 
surface temperatures with an upwelling over the upper part of the 
continental slope at the time of our visit, whatever may have been the 
case earlier in the season, because if such a process had been taking 
place, the cold water over the shelf would have been continuous with 
the cold water at greater depths further off shore, instead of separated 
from the latter by the warm bottom zone, which was found south of 
Cape Cod and Long Island; and which probably extended to Chesa- 
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