Cole, P. Bordalo, N. Christakis, C. Rosenberg, M. Liberman, J. Sheidlower, B. Zimmer, R. Darnton, and A. Spector for discussions; to C- M. Hetrea and K. Sen for assistance with Encyclopaedia Britannica's database, to S. Eismann, W. Tre, and the City of Berlin website (berlin.de) for assistance documenting