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POPULAR SCIENCE REVIEW. 
of the Caribbean Sea, through the passage between Hayti 
and Cuba. This water being forced into a sort of funnel, by 
the 500-fathom line forming the southern line of the Great 
Bahama Island, which connected nearly the whole of the Ba- 
hamas with Cuba, and formed a barrier to the western flow of 
the equatorial current ; this must, therefore, for the greater part, 
have been deflected north, and either swept in a north-easterly 
direction, as the Gulf Stream now does, or round the north end 
of the Bahamas, across Florida, which did not then exist, across 
the Gulf of Mexico, and into the Pacific over the Isthmus of 
Tehuantepec. To Commander Bartlett’s interest in this subject 
I am indebted for the first information respecting the lines run 
between the islands : 
Extract from Letter of Commander J. R. Bartlett , TJ.B.K. 
“ I connected the islands by running traverses across the 
ridges. From St. Vincent to St. Lucia the ridge was only from 
150 to 170 fathoms below the surface, with a channel of 400 
fathoms near St. Vincent. The channel between St. Lucia and 
Martinique had 500 fathoms in mid-channel, sloping upward to 
each island. The channel between Martinique and Dominica 
was a tough one, and I thought I should never find a ridge. 
The soundings increased regularly on a ridge to 300 fathoms in 
mid-channel, where I got a sounding 883 fathoms, and then 
1,000 fathoms; beyond this the ridge was some ten miles to 
the westward, with an average depth of 400 fathoms, but I 
found two peaks with only 40 fathoms. The deep water from 
the Caribbean Sea makes in between Guadeloupe and Mont- 
serrat, but I found a ridge of about 300 fathoms connecting 
Antigua with Guadeloupe. In this channel I also found a peak 
with only 40 fathoms. I finished up the line connecting 
Saba Bank with St. Croix. I found the connection perfect, but 
the ridge has 700 fathoms water on it near St. Croix. There is 
1,000 fathoms three miles north, and 1,800 fathoms five miles 
south of the ridge. I ran a line from Dog Island to White 
House Shoal, and back to Sombrero. Here I found a channel 
about ten miles wide with 1,100 fathoms. The temperature 
was 38° at 1,100; outside 37^° at 1,600; and 36^° at 2,500. 
I shall run a number of lines from St. Thomas to Sombrero, to 
be sure that this channel connects with the deep water off St. 
Thomas. I ran a line of soundings from the south end of 
Dominica to Avis Island. The soundings were regular at 1,000 
fathoms, to within ten miles of Avis Island.” 
The soundings made by Commander Bartlett, after I left the 
Blake , to determine the ridges uniting the various islands be- 
