Arrange these landmarks in the professionalisation of sociology, earliest first.

1. Hull House is founded in Chicago
2. The first American university department of sociology opens
3. The American Journal of Sociology is founded
4. Du Bois publishes The Philadelphia Negro
5. Thomas and Znaniecki begin publishing The Polish Peasant
6. Parsons publishes The Structure of Social Action
7. Mills publishes The Sociological Imagination

Putting Hull House and Du Bois at the front changes the story. On the usual telling, empirical urban sociology begins with the Chicago department; on the dates, two of its central techniques, mapping a district and surveying it house by house, were in use before or alongside it, by people the discipline did not employ.