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 beaches.
3) Mention of a Major White. Airy's thoughts and theories about the movement of shingles on the beaches.
4) Mentions sending his children underground to measure the heat below the surface. Mentions Sir William Denison's letter regarding his boat journey on the western coast of India and the stink of fish in the water.
5) Explains the details of Sir William Denison's letter, gives his own theories regarding the poisoning of the fish and the smell.
6) Part of the actual letter Airy received by William Denison explaining his journey from Mangalore India to Cananare and the annual impact of the S.W. monsoon on the fish.
7) Answering Lyell's questions from a previous letter regarding the earth's orbit. Mentions his first assistant W.Stone is conducting a study regarding the subject.