Read the extract below and answer the question: ......O, when mine eyes did see Olivia first, Me thought she purged the air of pestilence; That instant was,...

The figure of speech used in the underlined expression is a metaphor. A metaphor is a figure of speech in which a word or phrase is used to describe something else, suggesting a comparison between the two things without using the words "like" or "as." In the underlined expression, the speaker is describing how he felt when he first saw Olivia. He says that he turned into a "hart," which is another word for a male deer. This is a metaphor, as the speaker is not literally turning into a deer, but is using the word to suggest that he was filled with desire and a sense of wildness, like a deer pursuing its prey. The use of the metaphor helps to create a vivid image of the speaker's emotional state and to convey the intensity of his desire for Olivia.