In the classic novel, Jem and Scout make it their mission to try to get Boo Radley to come out of his house. They had heard all the rumors about him, and they wanted to see him for themselves. Atticus had told them many times to leave the Radley's alone, but they are kids and are very curious.
Jem and Scout find several things in the knot-hole of the old oak tree on the Radley property. The children are very curious as to who has left these things there. Later in the book they realize that it is Boo who is leaving these little gifts. He is trying to show them his affection for them. In the knot-hole they find 2 sticks of gum, a pack of gum, 2 old Indian head coins, gray twine, soap figures carved to like Jem and Scout, old spelling bee medals and an old watch on a chain and an aluminum knife.
"Two live oaks stood at the end of the Radley lot; their roots reached into the side road and made it bumpy. Something about one of the trees attracted my attention. Some tin foil was sticking out of a knot-hole just above my eye level, winking at me in the afternoon sun. I stood on my tiptoe, hastily looked around once more, reached into the hole, and withdrew two pieces of chewing gum minus their outer wrappers."
Jem and Scout don't realize it yet, but the person leaving these things for them will be the person who saves their lives. The person they have spent so much time trying to get to come out of his house, is the person who watches them and feels a deep connection to the both of them.
Arthur 'Boo' Radley is the reclusive individual who piques the interest and imagination of the children throughout the novel. Boo Radley's father was a strict "foot-washing Baptist" who kept Boo inside the house for most of his life. Boo is lonely and attempts to communicate with Jem and Scout by placing objects in the knot-hole of a tree inside his yard. The objects left inside the tree are signs of friendship. Boo gives the children sticks of gum (Wrigley's Double Mint), two shiny Indian coins, grey twine, soap figures resembling Jem and Scout, old spelling bee medals, an old watch, and an aluminium knife. At first, Jem and Scout think the knot-hole is somebody's hiding place until they begin to receive additional gifts in the knot-hole on a regular basis. The children still don't know Boo is giving them gifts but decide to write a thank-you letter. When Jem attempts to put the thank-you letter into the knot-hole, he sees that it has been filled in with cement. Nathan Radley, Boo's brother, filled the knot-hole with cement in order to end the communication between Boo and the children. Boo's magnanimous personality is revealed at the end of the novel when he saves both Jem and Scout from their attacker. Despite the loss of communication via the knot-hole in the tree, Boo never loses interest in the children and his selfless act of courage affirms their strong friendship.
Sticks of gum (Wrigley's Double Mint), 2 old Indian coins, Gray Twine, Soap figures, carved in the shape of Jem and Scout, A pack of gum, An old Spelling Bee medal and An old watch on a chain with an aluminum knife.
Jem and Scout find a variety of gifts in the oak tree left for them by Boo Radley. These include the following items:
1-Sticks of gum (Wrigley's Double Mint)
2-2 old Indian coins
4-Soap figures, carved in the shape of Jem and Scout
5-A pack of gum
6-An old Spelling Bee medal
7-An old watch on a chain with an aluminum knife
Hope this helps...