Metaphor is the literary device in which two disconnected/different things are compared. Simile is also a comparison between two disconnected things, but simile uses words such as "like" or "as", while metaphor simple states that "one thing is another".
"<em>The crest of each of these waves was a hill</em>, from the top of which men surveyed, for a moment, a broad tumultuous expanse, shining and wind-riven." - Metaphor.
"As each wave came, and she [the boat] rose for it, <em>she seemed like</em> a horse making at a fence outrageously high." - Simile.
Personification gives human characteristics to objects, animals or ideas.
"If <em>this old fool woman, Fate</em>, cannot do better than this..." - Personification.
Symbolism is when a word is used to symbolize something else. In this example, "uncertainties" represent the waves.
"The open boat is described as 'bobbing along among the universe's uncertainties." - Symbolism.
