When the children write a thank-you letter to the anonymous gift-giver in chapter 7, Jem attempts to leave the note in the knothole of the Radley tree, only to discover that it has been filled in with cement. When Jem questions Nathan Radley about why he filled the knothole of the tree in with cement, Nathan lies to Jem and says that he did it because the tree was dying. Knowing that his father would never lie to him, Jem asks Atticus if he thinks the tree is dying, and Atticus says that it looks perfectly healthy. At this moment, Jem realizes that Nathan Radley has purposely lied to him, and his chances of possibly communicating with Boo Radley are over. Later that evening, Scout observes that her brother has been silently crying on the porch, which provides insight into Jem's feelings regarding the unfortunate situation. Jem's tears are significant because they indicate a loss of childhood innocence. Nathan Radley's lie was the first time Jem recognized that an adult lied to him, which is a rather traumatic, eye-opening moment for him. Jem also cries for Boo Radley, which reveals that he is developing empathy and maturing. Jem realizes that Boo's seclusion is forced and sympathizes with his difficult situation.