The City below the Hill http://en.wikipedia.org/wiki/Second_Industrial_Revolution At the turn of the century the world went through the second industrial revolution (aka Technological Revolution)
Lasted from 1860s until WWI http://archive.org/stream/thecitybelowhill00ames#page/n0/mode/2up (The online version of the book Ms Novick mentioned)
A documented example of contrasting neighbourhoods at the turn of the century was in the city of Montreal: The south-western half of Montreal had noticeable differences above and below the hill.
The west side was nicknamed “City above the hill” the name coming from its higher ground. Residents of this area were white-collar workers. They remained ignorant of the situations of people below the hill, comparable, according to the book to their knowledge of the condition of natives in Central Africa. No poor at all can be found in this area of the city.
The east side was called the city below the hill. Salaried people and professionals only represented 15% of the population. The rest were blue-collar workers. At the time of the survey, 38000 people lived in this part of the city.
Stats:
FAMILY COMPOSITION * 7,671 families * 37,652 people * 25,051 people of working age (16+) * average of 1.64 children, .91 children, .73 infants (per family) * one block = home of around 147 people
Labour stats * 1442 places of labour * 16237 people find work in these establishments * 2000 employers * male&female workers 10,853 * home-tenders 11,720 * 2478 lodgers (may or may not be wage earners) * every 42 wage-earners: 33 grown males, 8 women, 1 child * 46 home tenders * 10 lodgers * 49 chilren * 27 school