Scope and Contents Letters are summarised as: 1) Explaining the theories of 'uniformity of the sea depth' in reference to equations from Mary Somerville and Pierre Simon de Laplace. Mentions seperate theory of absolute depth in relation to the moon and tides. Adds personal views on Somerville and De Laplace's theories. 2) Mentions Charles Henry Davis (US Navy - researcher of tides and currents) paper on the winds impact on tide direction and the the winds influence on the movement of shingle...