Definition of Metaphor
In Chapter 17, Poirot describes the psychology of the person he believes killed Roger Ackroyd. He employs a metaphor to describe the mindset of a blackmailer-turned-murderer, foreshadowing his eventual accusation of Sheppard himself:
Here is a chance of money—a great amount of money. He wants money—he desires it—and it is so easy. He has to do nothing for it—just keep silence. That is the beginning. The desire for money grows. He must have more—and more! He is intoxicated by the gold mine which has opened at his feet. He becomes greedy. And in his greed he overreaches himself.
In Chapter 18, Poirot tells Sheppard over dinner that he suspects something about Charles Kent but does not specify what. Sheppard uses a metaphor to describe Poirot's process of investigation and deduction:
Unlock with LitCharts A+I know now that the whole thing lay clearly unravelled before him. He had got the last thread he needed to lead him to the truth.
But at the time I had no suspicion of the fact. I overestimated his general self-confidence, and I took it for granted that the things which puzzled me must be equally puzzling to him.