which ran out to the very end, without finding bottom. Here
therefore in mid-ocean the depth exceeded 27,600 feet. One of
the shallowest soundings ever obtained in the open sea during
the same survey, struck bottom with 2677 fathoms, or 16,062
feet, latitude 33 degrees 21 minutes S., longitude 9 degrees 4
minutes E. The surveyors arrived at the conclusion, that at a
moderate distance from the shore, the depth of the great ocean
always exceeds 4000 feet.

During the American survey in 1849, a much greater depth, or
5700 fathoms (34,200 feet), was sounded in the Atlantic by
Lieut. Walsh, without reaching the bottom, in lat. 31 degrees 59
minutes N., long. 58 degrees 43 minutes W., or between the
Bermudas and the Azores. But the deepest soundings yet published
were taken Oct. 30th 1852, by Capt. Henry M. Denham, R. N., who
reached bottom at 7706 fathoms (46,236 feet), lat. 36 degrees 49
minutes S., long. 37 degrees 6 minutes W., the nearest land
being at the mouth of the River Plate. A weight of 9 lbs. was
attached to the line, which was one-tenth of an inch in
diameter; the day was calm, and the line took 9 hours 24 minutes
to run out. When the bottom was struck the line was raised 50
fathoms, and then allowed to run out again. It struck at the
same point as before, verifying the observations. Nevertheless
some experienced surveyors have remarked that the experiment
would have been more satisfactory had the weight been greater.
The highest summits of the Himalaya are about 28,000 feet; the
Pacific, according to this sounding, is probably at some points
twice as deep as the Himalaya are high.

[186] Mr. Hopkins, reasoning on data furnished by Dove's
Isothermal maps, has arrived at the very interesting
conclusion, that both on Snowdon and the lower mountains of the
West of Ireland the snow-line would descend to within 1000 feet
of the sea level, and glaciers reach the sea, if we could
simply assume the three following geographical changes:--

1st, The diversion of the Gulf stream from its present
northerly course; 2dly, the depression of the existing land of
Northern and Western Europe, to the amount of no more than 500
feet; and 3dly, a cold