Page:Polar Exploration - Bruce - 1911.djvu/173



first step in marine biological investigations, whether in the Polar sea or elsewhere, is the study of the physical conditions under which the marine forms of animals and plants live, and correlation of these observations in various seas. Hence the study of the physics of the oceans as a whole is most important, and it becomes the duty of a Polar explorer to carry on that research in the Polar seas. The first essential in any form of oceanic research, after knowing one's position on the earth's surface, is to know the depth, and if this has not already been determined one must take a "sounding." To be able to sound accurately in all depths is the first accomplishment of the practical oceanographer. In the Arctic Regions bathymetrical survey has been of the most irregular and piecemeal character, although on the whole we have now a fairly complete knowledge of the conformation of the floor of the North Polar Basin and the seas adjacent. Most of these soundings have been secured in the course of ordinary navigation, but Sir John