Definition of Metaphor
In Volume 2, Chapter 6, Caleb finally gets Falkland to privately confess that he murdered Tyrell and framed the Hawkinses. Afterwards, an allusion helps Caleb express his realization that he has turned himself into a metaphorical prisoner in Falkland's house:
The ease and light-heartedness of my youth were for ever gone. The voice of an irresistible necessity had commanded me to ‘sleep no more.’ I was tormented with a conscious secret of which I must never disburthen myself; and this consciousness was at my age a source of perpetual melancholy. I had made myself a prisoner, in the most intolerable sense of that term, for years, perhaps for the rest of my life.
In Volume 3, Chapter 8, Caleb goes to London to try to hide from Falkland and the law, among the masses and under an assumed identity. He uses a prescient metaphor to explain how he keeps his spirits up, foreshadowing his slide into tyranny at the end of the novel:
Unlock with LitCharts A+Whether life were worth my accepting on such terms I cannot pronounce. I only know that I persisted in this exertion of my faculties, through a sort of parental love that men are accustomed to entertain for their intellectual offspring; the more thought I had expended in rearing it to its present perfection, the less did I find myself disposed to abandon it. Another motive not less strenuously exciting me to perseverance, was the ever growing repugnance I felt to injustice and arbitrary power.
In Volume 3, Chapter 12, Jones kidnaps Caleb from the heath and drags him to the back room of an inn, where Falkland is waiting for him; when Caleb finally sees his tormentor after so long, he is struck by how terrible Falkland looks. The passage uses imagery in service of a compelling metaphor:
Unlock with LitCharts A+His visage was haggard, emaciated and fleshless. His complexion was a dun and tarnished red [...] and suggested the idea of [his face] being burnt and parched by the eternal fire that burned within him. His eyes were red, quick, wandering, full of suspicion and rage [...] His whole figure was thin to a degree that suggested the idea rather of a skeleton than a person actually alive. Life seemed hardly to be the capable inhabitant of so woe-begone and ghost-like a figure. The taper of wholesome life was expired; but passion and fierceness and frenzy were able for the present to supply its place.
In Volume 3, Postscript, Caleb addresses the now-deceased Falkland. He uses a metaphor to lament the situational irony of Falkland's disgraced demise:
Unlock with LitCharts A+Thy intellectual powers were truly sublime, and thy bosom burned with a godlike ambition. But of what use are talents and sentiments in the corrupt wilderness of human society? It is a rank and rotten soil from which every finer shrub draws poison as it grows. All that in a happier field and a purer air would expand into virtue and germinate into general usefulness, is thus converted into henbane and deadly nightshade.