BIGELOW: COAST WATER EXPLORATION OF 1913. 245 
terranean and in the Red Sea, and a similar error runs through Libbey’s 
whole series of subsurface densities. As just pointed out it can not 
be charged to the instruments, and in absence of information as to how 
soon the observations were made after the samples were collected, 
there is no means of judging whether it can be laid to evaporation of 
the samples. But whatever its origin, it is useless to attempt any 
reconstruction of the density curves along his profiles. Had this been 
possible, it would have’thrown light on the origin of the cold tongue 
which Libbey suspected was a “mechanical intrusion of cold water 
from the surface of the continental platform, reinforced by the specific 
gravity of the water” (1891, p. 407), as was certainly the case in 1913. 
In the neighborhood of Woods Hole, Sumner, Osburn, and Cole 
(1913) took a considerable series of hydrometer readings, checking 
them from time to time by titration. And though from their very 
nature they can not claim the accuracy of the latter method, yet their 
averages must be very close to the truth. They found the mean 
salinity of Vineyard Sound in July and August about 32.2% 9 which 
agrees very well with our record of 32.29%p off the entrance to Vine- 
| yard Sound (Station 10084). Dickson’s (1901) charts show the water 
immediately south of Marthas Vineyard as 32%p in July, 1897, with 
the salinity 33% o and higher over the 100 fathom contour. In 
August of the same year, the coast water between Delaware Bay and 
| Nantucket Shoals was below 32% o bounded seaward by a zone of 
\water with salinity between 32% and 33%p over the outer part of 
|the continental shelf. These charts, taken at their face value, sug- 
gest that the salinity was considerably lower in 1897 than in 1913, for 
‘im July of the latter year water fresher than 32%p was confined to a 
small area off the mouth of the Hudson River, and along the south 
shore of Long Island. But the records on which they are based are 
$0 few that it is a question whether there actually was any such 
ilifference between the two years. And Schott represents the salinity 
of the water over the continental shelf between Cape Cod and Chesa- 
peake Bay as 32-33%po (1902, taf. 33). Further information as to the 
jalinity of our coastal zone is contained in the Bulletins of the Inter- 
rational Conseil for the exploration of the sea. In August, 1907, 
ond February, 1908 (1909), the water along the coast of Nova Scotia 
vas 32%p or less; the curve for 32% touching Cape Cod in the latter 
aonth. And the curves for May of that year afford the interesting 
formation that 32% water spread seaward in an obtuse wedge, 
poe of the Gulf of Maine, and that water of that same salinity 
: 
athed the coast as far as New York. Unfortunately there were no 
| 
| 
| 
| 
| 
