http://archives.econ.utah.edu/archives/pkt/2000m03/msg00238.htm
http://archives.econ.utah.edu/archives/pkt/2003m03/msg00147.htm
The second includes a passage from Russell acknowledging that Whitehead had managed to demonstrate to him that the grounds on which he had rejected the idea of "internal relations" (which Russell here identifies with Hegel) were mistaken. This did not not, however, lead him to abandon his "atomism", i.e. his view that the world is ultimately reducible to an immense number of externally related bits.
"I am persuaded that the world is made up of an immense number of bits, and that, so far as logic can show, each bit might be exactly as it is even if other bits did not exist." (Bertrand Russell, "Beliefs: Discarded and Retained", in Portraits from Memory, p. 42)
Ted