Where in To Kill a Mockingbird do Jem and Scout find out that Boo Radley is the one leaving gifts in the tree for them?

In
,andbegin receiving several small gifts in the knothole of the Radley tree from an anonymous
gift giver. The children receive a ball of gray twine, a whole package of chewing gum, and two
carved soap dolls. Initially, the children believe the knothole is someone's hiding spot and
wonder if Mr. Avery carved the soap figures and put them in the tree. Later on, the children
receive an old spelling bee medal, a broken pocket watch, and an aluminum knife. While Scout has
no idea of the anonymous gift giver's identity, Jem has a feeling thatis the person leaving them
small gifts. When Jem decides to leave the anonymous gift giver a note in the knothole of the
tree, Scout metions that he debated on tellingabout their situation. Scout then says,

He [Jem] had been on the verge of telling me something all evening;
his face would brighten and he would lean toward me, then he would change his mind. He changed
it again. (Lee, 16)

Whiledoes not explicitly...