Silver Fever
The novel is about the effects of greed stimulated by precious metals. Typically, this plot would involve gold, but here it is silver. “There is something in a treasure that fastens upon a man’s mind." This metaphor encapsulates the essence of the tale. It is a symbolic manifestation of the idea of greed for the wealth of silver infecting the processes of rational thinking. This infection leads to the rise and downfall of Nostromo.
Suicidal
A densely packed and poetically framed use of similes reveals the depth of depression which will lead one character to suicide. To this man, left alone on a deserted alone to guard a wealth of treasure he can never own, "the solitude appeared like a great void, and the silence of the gulf like a tense, thin cord to which he hung suspended by both hands, without fear, without surprise, without any sort of emotion whatever." This metaphorical imagery paints a symbolic portrait of looking out upon an ocean to the horizon with knowledge that escape is impossible without rescue. The abyss of hopelessness culminates in the comparison to a metaphorical hanging which foreshadows an eventual suicide by gun.
Gender
The patriarchal control of women by force is juxtaposed against the feminine tools of subversive rebellion using metaphor. "A woman’s true tenderness, like the true virility of man, is expressed in action of a conquering kind." Mr. Gould is an exploiter of men who revels in his masculinity by lording his privilege over others. His long-suffering wife is therefore charged with engaging in social discourse with those who are inevitably under the thumb of her husband's oppression. Naturally, these people are not exactly happy. The location of virility and femininity in the language of war suggests that a husband and wife of privilege are not really so different.
Darkness
Nostromo was published at the dawn of the last century. That century would go on to produce literature which situated darkness as the defining metaphor of the modern age. “The darkness is our friend." Nostromo is here making a metaphor out of actual literal darkness, such is the flexibility of its metaphorical capacity. The protection of a treasure trove of silver which has failed to reach its destination is facilitated by the disappearance of sunlight, In the sunset, darkness has become an ally in the ability to protect the treasure from being discovered by enemies.
The Lighthouse
The construction of a lighthouse becomes a symbol. The symbolic essence of the lighthouse is couched in one very specific metaphor. Nostromo "was struck with amazed dread at this turn of chance, that would kindle a far-reaching light upon the only secret spot of his life; that life whose very essence, value, reality, consisted in its reflection from the admiring eyes of men." Within the darkness of guilt and paranoia that is Nostromo's mindset, the lighthouse beacon becomes a searchlight in which every circling about threatens to become the moment that reveals his moral downfall. He is a man who rose to greatness based largely upon reputation and the light presents a literal threat of revealing his hypocrisy.
