ABSTRACT
DURING the Renaissance man's knowledge of the world around him expanded as never before and the rise of experimental science opened up new dimensions of understanding. But the disparity between the kind of information which sailors provided on the movements of water in the sea and the requirements of philosophers in search of an explanation of cosmic processes meant that ambitious theoretical developments outpaced the inadequate supply of factual material. As a result of gradual improvement in understanding of the physical properties of fluids, inferences could be made, and sometimes were, about the state of the ocean; for example that the pressure of the ocean at any place on its bed was determined solely by the depth of water there and had nothing to do with the volume of water as a whole, a point brought out by Mersenne in his Cogitata PhysicoMathematical In other respects scientists discussed the sea in terms which had not changed since the days of Aristotle. If this situation was to be altered it was necessary for them to make a first hand examination of actual conditions in the sea. In Britain during the second half of the seventeenth century the broadening of the scientific outlook and the development of instruments led to this being done.
