On the Road Part 1, Chapter 8
Everyone was planning a trip to the mountains. Eddie, the hitchhiker, has ended up in Denver and calls up Sal. They go to investigate Dean's promised job together. It is a 14 hour-a-day job. The next morning Eddie shows up, but Sal doesn't. Carlo writes dismal poetry calling Dean a "child of the rainbow". Dean announces that he is going to divorce Marylou and marry Camille. In the middle of one of their Benzedrine moments, Carlo asks Dean if he has gotten to the bottom of his soul.
"'That last thing is what you can't get, Carlo. Nobody can get to that last thing. We keep on living in hopes of catching it once for all.'" Part 1, Chapter 8, pg. 48
Sal thinks that the pair cannot get where they are going and listens to them talking all night as he drifts in and out of sleep. He calls them "amazing maniacs". He goes home the next day.