Salinger uses strong, violent tactile imagery as Holden recounts being unable to restrain himself from hitting Ward Stradlater. He surges up and punches the other boy as Stradlater smugly discusses his date with Jane:
This next part I don’t remember so hot. All I know is I got up from the bed, like I was going down to the can or something, and then I tried to sock him, with all my might, right smack in the toothbrush, so it would split his goddam throat open. Only, I missed. I didn’t connect. All I did was sort of get him on the side of the head or something. It probably hurt him a little bit, but not as much as I wanted. It probably would’ve hurt him a lot, but I did it with my right hand, and I can’t make a good fist with that hand. On account of that injury I told you about.
The tactile imagery here gives the reader an unpleasantly close view of Holden’s violent outburst. Since his brother Allie’s death, Holden has expressed his grief by violently venting his anger and frustration. Holden describes his attempt to punch Stradlater "right smack in the toothbrush," intending to "split his goddam throat open" in unpleasantly vivid detail here. The punishment far exceeds the scope of Stradlater’s crime, but Holden is so overcome with rage that he blacks out, saying he doesn’t “remember it so hot.” His admission that the punch "probably hurt [Stradlater] a little bit, but not as much as I wanted" further emphasizes his desire to channel his emotional pain into physical action. He can’t do anything about Allie’s death, so he takes it out on someone he sees as epitomizing the bad things and "phoniness" he hates.
Holden hears a child singing the "Catcher in the Rye" song in the street as he heads glumly to buy Phoebe a record. This sweet, nostalgic moment of auditory imagery breaks him out of his bleak mood and makes him feel better:
He was singing that song, “If a body catch a body coming through the rye.” He had a pretty little voice, too. He was just singing for the hell of it, you could tell. The cars zoomed by, brakes screeched all over the place, his parents paid no attention to him, and he kept on walking next to the curb and singing “If a body catch a body coming through the rye.” It made me feel better. It made me feel not so depressed any more.
Holden's mood has been steadily deteriorating; by this point, he's glumly dwelling on the fact that nuns don't get to go for fancy lunches. As he passes in front of a church, however, he hears a child happily singing a song. He's delighted because the child is singing "for the hell of it," singing just to sing and with no regard for what anyone else thinks. His parents are annoyed with him, but the child continues to sing to entertain himself. The auditory imagery is striking here, as the child's "pretty little voice" pierces through all of the "zooming" and "screeching" of the cars around him. It's another moment when Holden enjoys what he sees as pure and unfettered childhood authenticity juxtaposed against the chaos and "phoniness" of the city.
Holden uses smell imagery and hyperbolic description to invoke the comforting, enveloping auditorium at the Museum of Natural History:
[...] [T]he inside of that auditorium had such a nice smell. It always smelled like it was raining outside, even if it wasn’t, and you were in the only nice, dry, cosy place in the world.
Holden loves the auditorium, and thinking about it spurs some of the most romantic associations for him that the Museum evokes. Holden recalls that the auditorium’s smell was "like it was raining outside, even if it wasn’t.” The imagery of smell in this passage evokes a sense of being deliciously inside when it’s bad outside, sheltered from the weather. Even if it isn’t raining outside, the auditorium feels so safe and inviting that, by comparison, it might as well be.
This passage is also an example of hyperbole, as Holden describes being in the auditorium as feeling like “you were in the only nice, dry, cosy place in the world.” The hyperbole draws the reader’s attention to the sense of refuge Holden feels here. Although, of course, there are safer places “in the world” than public libraries, to Holden it’s the ultimate sanctuary. He often feels anxious and depressed in other settings, but the library makes him feel welcomed and safe.