Croll, James, 1821-1890 (physical geologist and Keeper of Maps and Correspondence, Geological Survey of Scotland)

Scope and Contents Letter to Sir Charles Lyell from James Croll concerning the effect of the build up of ice during the glacial epoch upon the level of the ocean and his belief that the level of the ocean would not be lowered by the accumulation of ice as the level of the water would adjust itself to the altered centre of gravity of the earth, 4 January 1866.

Scope and Contents Letter to Sir Charles Lyell from James Croll regarding modifications he has made to his Submergence Theory which held that the level of the ocean would not be lowered by the accumulation of ice due to Lyell passing on some calculations as to the amount of water needed from the oceans to form an ice-sheet of sufficient mass to alter the earth's centre of gravity. He encloses a letter to the Reader to put the matter straight and asks for Lyell's approval. 6 January 1866.

Scope and Contents Letter to Sir Charles Lyell from James Croll concerning the extent to which the centre of gravity of the earth would be displaced by ice caps 2000 feet and 3000 feet thick, 16 February 1866.

Scope and Contents Letter to Sir Charles Lyell from James Croll concerning calculations of Charles Moore's which Lyell had sent to him and discussing his own calculations which show how much the centre of gravity of the Earth would have been displaced by the weight of ice-caps, 17 February 1866.