There is no doubt that people are growing more and more interested in the seas, and that there is a great need for that interest. Men have long tried to probe the secrets of the oceans to gain knowledge for its own sake, but there are other practical reasons for doing so. The sea can provide us with many things that we need in everyday life. Future generations will probably draw more on the seas for their food, and not only food in the form of fish. Minerals necessary for modern industries are there also, when we can find out how to extract them.
We have explored and mapped most of the land, and we are quickly exploring the air. The seas present a greater difficulty because we cannot yet, and probably never shall, be able to set foot on the deep ocean floor.
The aim of the extensive oceangoing expeditions, and of the marine biological stations around the coasts, and even of those who simply study the shore uncovered by the tide, is to build up our knowledge of this vast and unfamiliar world beneath the waves. In some cases the knowledge gained can be put to practical use, but much of it is for interest only.
For the very early mariners, interest lay in the currents, and especially those at the surface, that carried their ships along. They were also interested in the weather over the sea. Yet, even these hard-bitten sea-men were not immune from a curiosity about the animals and plants that lived below the waves. Their first impulse may have been to seek trade overseas, or to fish for food, but over and above this anything strange or beautiful, whether brought up in their nets or cast ashore by the tides, caused them to wonder. So, from the earliest time, the pursuit of the practical every day things went on side by side with the inquiry that springs from a desire to know more. Bit by bit grew the knowledge of the physical features of the seas, of such things as currents, waves, and winds, as well as of the biology, the knowledge of animals and plants.
