The writer who helped bring about the breakup of the Standard Oil monopoly was Ida Tarbell, who was one of the original muckrakers.
The infinitive here is 'to leave', and it is used as an 'adverb', meaning 'with the intention to leave', since it modifies a verb, it has to be an adverb.
<span>Trumbull uses words such as dim, slumber, clouds, and darkness to describe British oppression. He contrasts these descriptions with phrases associated with light such as "golden days" and "boundless skies," which signify a free nation.</span>