 For Galileo , the tides were caused by the sloshing back and forth of water in the seas as a point on the Earth 's surface sped up and slowed down because of the Earth 's rotation on its axis and revolution around the Sun . He circulated his first account of the tides in 1616 , addressed to Cardinal Orsini . His theory gave the first insight into the importance of the shapes of ocean basins in the size and timing of tides ; he correctly accounted , for instance , for the negligible tides halfway along the Adriatic Sea compared to those at the ends . As a general account of the cause of tides , however , his theory was a failure . 
