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supplied from the Polar area. I will show you how this supply 
takes place. Here, for instance, in this Lightning Channel, we 
found that we could distinctly trace it along near to the comer 
of the Faroe Banks ; and though we had not the means (which 
I hope we may at some future time) of measuring its move- 
ment, yet by the nature of the bottom we felt pretty sure that 
it was a running stream, for the pebbles there instead of being 
angular were round — which you know is a distinct indication 
of a current. Well, then, we have every reason to believe that 
this stream ran on and discharged itself into the great Atlantic 
basin. For about 100 miles to the westward of this there is a 
deep slope, going down to 1,500 or 2,000 fathoms ; and thus 
it would be one of the feeders, so to speak, of the great mass 
of Polar water in the Atlantic, basin. Then between the Faroe 
Islands and Iceland there is a shallow bank ; but between Ice- 
land and Greenland, again, there is a wide and deep channel, 
through which a very large mass of Polar water can come down. 
And though no temperature-soundings have yet been made (so 
far as I am aware) in this channel, yet the character of the 
bottom, as shown in the 44 Bull-dog ” soundings, corresponded 
so closely with that of our own cold area, as to justify the 
belief that the deep water is glacial. Now water cannot be 
always flowing out of the Polar basin, without water from some 
other source flowing into it ; so that if there is such an outflow 
at its bottom, the circulation must be completed by a constant 
mflow of mr/ace-water. While, then, the deeper water is coming 
from the Pole, there must be mr/ace-water going towards the 
Pole. 
You have all heard of the G-ulf Stream. It is a great mass 
of water issuing from the G-ulf of Mexico through the channel 
between the peninsula of Florida aud the Bahama Islands, and 
flowing in a north-easterly direction. The very powerful cur- 
rent that passes through that narrow channel, flows at first at 
the rate of three or four miles an hour in a direction which 
carries it towards the Banks of Newfoundland and the Azores ; 
and it is popularly believed to flow on towards the northern 
coast of the British Isles, and thence to Spitzbergen, Iceland, 
and even Nova Zembla. Now I have every reason to believe, 
from careful inquiries lately made, that this Gulf Stream really 
has not much to do with the phenomena of which I have been 
telling you, and that its influence pretty much ceases not far 
to the eastward of the banks of Newfoundland. The G-ulf Stream 
is part of the horizontal circulation in the North Atlantic. I 
think you will easily understand the difference between a hori- 
zontal circulation and a vertical circulation. Look at the 
w T ind ruffling the surface of a pond. It blows the water in a 
particular direction, and produces little ripples. If it drives 
