The unceasing stream of deep‐sea soundings from national and institutional vessels of countries bordering or having interest in the ocean, among which those of the Unites States have made a large contribution, is year by year advancing to a nearer stage of realization the once distant prospect of mapping the conformation and topography of the bottom of the ocean.I will not ask you to ascend the steps by which the present stage of progress has been reached, but, in association with my endeavor to convey to you an impression of the accumulations that have been gathered, I would have it recalled that in the middle of the nineteenth century—which marked the close of the period of coast reconnaissance and island discovery following the period of circumnavigation and continent discovery—the sea remained unfathomed, excepting in the shallower waters bordering the land where there were in progress, as national undertakings in aid of commerce and navigation, those marine hydrographic surveys which have eventually made the coastline of the world the best known of the major geographical features of the world. In that unfathomed state, while the former and present role of the ocean, in the history of the Earth and its economy, did not go unnoticed, oceanography had not yet forged those bonds of kinship which now relate it to many other branches of science, and which augment its im