However, Jim's character is known for his adventurous spirit and his willingness to take risks, which could lead to him having "mad notions" or ideas that might seem foolish to others.
To get a better understanding of what you're looking for, could you please provide some context or details about the situation you're referring to? For example:
* What was happening in the story at that point?
* What was Jim thinking or doing that might have been considered a "mad notion"?
* What were the potential consequences of his actions?
With more information, I can help you pinpoint the specific "mad notion" you're interested in.