remarkable factTthat, throughout the entire distance, nearly 200 miles, between
the point at which this sounding was taken and the Faroes, not the slightest
trace of Aolcamc detritus appears in the material brought up from the bottom.
Between long. 7° 55' and 13° 45' inclusive, eleven casts were made, and bottom
brought up five times; so that, had volcanic particles been present, some trace of
them must at all events have been observable. This becomes the more remarkable
when it is home in mind that, during eruptions of Hecla and Skaptar
Jokul, the volcanic particles have been borne across the whole breadth of the
North Sea, to the coast of Nonvay, in nearly the same parallel of latitude as
the Faroes. I t is difficult, therefore, to conceive that this large area of sea-bed,
or at any rate that portion of it constituting the middle third of the distance
alluded to, should not have received a share of the deposit, under favourable
conditions as to atmospheric currents.
On the other hand, from the 682-fathom locality to our present position,
which I should say is not more than forty miles from the southern shore of
Iceland, out of eight casts, seven on being brought up have each presented volcanic
detritus.
Combining all these facts together, I am clearly of opinion that a deep-seated
drift, bringing the colder waters from Spitzbergen and the western side of Nova
Zembla, sets along this middle tract and bears away with it the volcanic debris.
We know that the Arctic drift splits up into two branches, as it were, on coming
across the northern shores of Spitzbergen; one branch, passing do™ to the
south-westward and carrying along m th it the mass of ice which hugs the eastern
coast of Greenland, doubles Cape Farewell, and then streams up along the
western shores of Greenland,—the other branch being traceable for several degrees
to the southward and eastward of Spitzbergen, and then graduaUy lost in the
fork of the Gulf Stream, the western arm of which ascends in a due northerly
dhection, so as to impinge against the southern portion of Spitzbergen, whilst
the other arm, turning aside at nearly a right angle, assumes an easterly course.
That branch of the descending or Arctic drift which is traceable into the bifurcation
of the ascending or Gulf Stream must find its way somehow to the Equator;
and, as a natural consequence, it follows the recognized practice of all cold
cun-ents when brought into contact with warmer ones, and thus travels below it
to its destination. Continued in its original course, this current would traverse
the middle space between the Faroes and Iceland; and, as has been sho™, if
moving at no greater velocity than 600 yards (that is, about one-third of a mile)
per hour, or half the speed at which we know the western superficial branch
moves round Cape Farewell, it would be quite powerful enough, independently
of the decrease in the specific gravity of particles of mineral matter owing to the
conditions already discussed, to bear along those particles and thus to remove all
trace of debris other than that reproduced by its o™ action. By means of this
current, the volcanic particles which, according to Captain Maury, strew the bed
of the Mid-Atlantic, between the parallels of 47° and 52°, along no less than
twenty-five degrees of longitude, are borne down from the Icelandic coasts. In
the “ Notes” * published by me immediately after my return from the cruise, I
adverted to this as being the true source of the volcanic matters present in the
latitudes referred to, and thus corroborated the shrewd suggestion of the late
Professor Bailey.
I think we are therefore wairanted in assuming that a current having a
moderate velocity, such as that referred to as being sufficient to account for the
phenomena in question, does exist, and that it flows away in a south-westerly
course, under the warmer waters of the ascending Gulf Stream, and gradually
mingles with the general gathering of the polar waters around the Equator,—an
additional proof of the correctness of this view being derived from the fact, fully
borne out by various navigators, that about the 63rd parallel of latitude the temperatures
of the surface-water and that at a hundred fathoms’ depth do not
usually differ by more than three degrees—clearly indicating that, at one-sixth of
the greatest recorded depth of water, the temperature of the Gulf Stream has
not yet been materially diminished, and, inversely, that the cold drift is still too
deep-seated to have been in operation at that distance from the surface.
iTiily 10.— Strong head winds, cold drizzling fogs, or drenching rain, with a
nasty chopping sea, have haunted us ever since we drew near to “ The Inferno,”
Our course lias been close to the northward of the Westmann Islands, a group of
purely volcanic origin, and abounding in magnificently bold scenery. Most of
the islands consist of trappean rock thnist up sheer from the sea to a height of
several hundred feet. In one place the entire face of one of these huge masses
has been rifted off and hurled forwards as it were, its angle of inclination being
* “ Notes on the Presence of Animal Life at vast Depths in the Sea.”