The accompanying diagram shows the results obtained.
These soundings prove the existence of a continental shelf covered by about 100 fathoms of water and whose edge, north of Cape Columbia, lies about 46 sea miles from the shore. In latitude 84° 29´ the depth was found to be 825 fathoms, while in latitude 85° 23´ it was found to be only 310 fathoms. This diminution in depth is a fact of considerable interest in reference to the possible existence of land to the westward.
The three soundings taken between the point of comparatively shallow water and the Pole failed to reach bottom. The one made within five sea miles of the Pole proved the depth there to be at least 1500 fathoms. This is not at variance with the northernmost sounding taken by the Fram, at a point north of Franz Josef Land and in latitude about 85° 20´, viz., 1640 fathoms and no bottom.
Tides.—Tidal observations upon the arctic coasts of Grant Land and Greenland were carried out under instructions from the Coast and Geodetic Survey, this Bureau having been ordered by President Roosevelt through the Secretary of Commerce and Labor to have such work undertaken.
The object was to secure observations along the northern coasts of Grant Land and Greenland at a sufficient number of places for determining the tides in this region; it being the belief that such observations might throw light upon the possible existence of a "considerable land mass in the unknown area of the Arctic Ocean."
Systematic tidal and meteorological observations were carried on day and night at Cape Sheridan, Point Aldrich (near Cape Columbia), Cape Bryant, Cape Morris Jesup, and Fort Conger—the periods of time covered at these stations being about 231, 29, 28, 10, and 15 days, respectively.[5]
The tides were observed upon vertical staves or poles held in position by means of stones placed around them at the bottom of the shallow water along the coast. At Cape Sheridan, Point Aldrich, and Cape Bryant igloos were built over the tide staves. These being heated, usually by means of oil-stoves, the observers were enabled to maintain open well-holes with comparative ease.
In order to secure fixed data of reference, permanent bench marks were established on the land, not far from the igloos or tide staves.