44 EXPLORATIONS, WESTERN ATLANTIC, STEAMER BACHE, 1914. 
interesting discovery made by the Bache, for it shows that the 
salinity of the water which flows into the Caribbean Sea through the 
bottom of the Windward Passage (between Cuba and Haiti), the 
Anegada Passage (between Sombrero and the Virgin Islands), and 
possibly the passages between Dominica, Martinique, St. Lucia, and 
St. Vincent, and thence into the Gulf of Mexico via the bottom of 
the Yucatan Channel, is unaltered during its sojourn there, a gen- 
eralization which also holds for temperature, as pointed out by A. 
Agassiz (1888, p. 220). 
The vertical distribution of temperature in the upper layers on 
the southern half of the Key West-Habana line is generally similar 
to that of the southwestern part of the Gulf and Straits of Yucatan. 
In spite of the interval of 40 years between the two sets of observa- 
tions, the temperature at Bache station 10021 agrees almost exactly, 
down to 800 meters, with the temperature encountered by the Blake 
on May 17, 1876, about 95 miles northwest of Habana, except for 
being cooler at the immediate surface, a difference to be expected 
because of the different seasons. And the slightly cooler water off 
Habana (station 10199) was almost exactly identical with the tem- 
peratures taken by the Blake in 1878 on the east side of the Yucatan 
Channel close to Cape San Antonio, except, as before, for a seasonal 
difference on the immediate surface. 
The much colder and fresher water off Key West must have a 
twofold origin. Probably it comes chiefly from the current which 
flows around the northern and eastern sides of the Gulf, following 
the 200-meter curve (British Admiralty, 1897; Soley, 1911). This 
current is considerably colder at all depths down to about 800 meters 
than the water in the central and southern parts of the Gulf, as 
shown by temperatures taken off Apalachicola, Fla., by the United 
States Fish Commission steamer Albatross* on March 13, 1885, 
receiving its low temperature from the cold water in the north- 
western part of the Gulf (Kriimmel, 1907). The water is even 
colder on the surface at this season along the north shore of the 
Gulf than in the Straits. However, this cold surface is confined to a 
very narrow belt (Deutsche Seewahrte, 1882) and is probably due to 
the cold ‘“northers’’ which blow so often in winter. 
The fact that, except for this shallow surface layer, the water was 
considerably colder close to Key West than the Albatross found it 
in the northern part of the Gulf (fig. 26), indicates that some up- 
welling was taking place from the deeps of the Gulf. Thus, tempera- 
tures suggest that the west end of the Straits is a condensed epitome 
of the Gulf as a whole, water from the north flowing around the 
Florida cays, from the center of the Gulf into the center of the 
a Dredging and other records of the United States Fish Commission steamer Albatross, etc.; Townsend, 
C. H.; Report United States Commission of Fish and Fisheries, 1900, p. 494, 
