Question: when do jem and scout find the knothole?
Answer: In chapter 4 of To Kill a Mockingbird, Jem and Scout begin finding objects left for them to discover inside a knot-hole of an oak tree at the Radley's. The first object Scout discovered was a piece of Wrigley's Double-Mint gum. The second object they find is a box with two polished Indian-head pennies.