54 EXPLORATIONS, WESTERN ATLANTIC, STEAMER BACHE, 1914. 
Only off Chesapeake Bay is the actual density of the mixed water 
known for winter. But inasmuch as winter cooling, off our coasts, is 
most rapid and most extreme next the land (Bigelow, 1915), while the 
salinity of the coast water, so far as known, rises during autumn and 
winter (Bigelow, 1915), it follows that the mixed is heavier than ocean 
water in winter all along our coast, as it certainly is off Chesapeake 
Bay (p. 49). 
But while the actual occurrence of a downpour over the slope can 
be considered as demonstrated off Chesapeake Bay in winter, and 
off Georges Bank in summer, our summer profiles across the shelf 
at intermediate points would be hard to reconcile with this type 
of vertical circulation (Bigelow, 1915). It is possible that a local 
Densit 
26 5 4 27 
ce 
24 5 29 5 
: = =e 
oS 
co 
19 
Fia. 53.—Density sections in the ocean water (Bache station 10161), and in the mixed water (Bache station 
10158), off Chesapeake Bay, January, 1914, and in the mixed water (Grampus station 10171), off Delaware 
Bay, July, 1913. 
dynamic tendency of this sort might be overridden by some more 
wide-spread type of oceanic circulation. But whether the down- 
pour be general for the zone over the continental slope, or only 
local or temporary, the fact that it actually occurs is one of the most 
interesting hydrographic results of the cruise of the Bache, for when- 
ever anything of the sort takes place the mixed water must play as 
important a réle in the manufacture of the deeper layers of the coast 
water on the shelf as it does in the Gulf of Maine. 
Finally, it is shown that there is nothing in the Bache or Roosevelt 
temperatures to suggest the ‘‘Arctic” current so often invoked off our 
coasts (Bigelow, 1915), the coast water being far too warm even in 
January. 
