Well, it has been a long time since I read the book (never saw the movie)
but surely 'Butterfield 8' refers to the telephone 'prefix' which in the
days before digit-dialing was BU 8.  If I recall, prefixes were
distributed geographically and BU(ttefield) 8 was in a fashionable
Manhattan neighbourhood.

When I grew up (many years ago) in San Francisco, my own telephone number
was WEst 1 - 5727, now more prosaically 931-5727.


...............................................................................

Dr M.D. Kaplanoff                                         Pembroke College
University Lecturer in American History                 Cambridge  CB2 1RF
Cambridge University &                                             England
Fellow of Pembroke College, Cambridge               phone: +44-1223-338151
                                                      fax: +44-1223-338163
History Faculty office (secretary, Ms Susan Pocock) phone: +44-1223-335304
                                                      fax: +44-1223-335968