During the second sequence, you will come across Benjamin Franklin on Boston. The famous inventor will ask you to recover pages from him almanac which are spread throughout Boston (20) and New York (16). As you approach one of them, it will be carried off by the wind. You will only have a couple seconds to reach and catch it. To do that, always approach the marked spots by jumping between roofs. That way you will save time which you would otherwise need to climb up. Don't worry if you don't manage to catch the page - move away to a different place and it will appear again.
Map of Boston
Map of New York