James Nasmyth, James Nasmyth, Engineer: An Autobiography
“ I had often the privilege of standing by and hearing the philosophic Leslie, Brewster, and Hall, discussing these volcanic remains in their actual presence; sometimes at Arthur's Seat or on the Calton Hill, or at the rock on which Edinburgh Castle stands, Their observations sank indelibly into my memory, and gave me the key to the origin of this grand class of terrestrial phenomena. When standing at the "Giant's Ribs," on the south side of Arthur's Seat, I felt as if one of the grandest pages of the earth's history lay open before me. ”
