Emily Dickinson Lexicon

IT, pron. [Sax. hit; D. het; G. es; L. id.]

1. A substitute or pronoun of the neuter gender, sometimes called demonstrative, and standing for any thing except males and females. “Keep thy heart with all diligence, for out of it are the issues of life.” Prov. iv. Here it is the substitute for heart.
2. It is much used as the nominative case or word to verbs called impersonal; as, it rains; it snows. In this case, there is no determinate thing to which it can be referred. In other cases, it may be referred to matter, affair, or some other word. Is it come to this ?
3. Very often, it is used to introduce a sentence, preceding a verb as a nominative, but referring to a clause or distinct member of the sentence. “It is well ascertained, that the figure of the earth is an oblate spheroid.” What is well ascertained? The answer will show: the figure of the earth is an oblate spheroid; it [that] is well ascertained. Here it represents the clause of the sentence, “the figure of the earth,” &c. If the order of the sentence is inverted, the use of it is superseded. The figure of the earth is an oblate spheroid; that is well ascertained. It, like that, is often a substitute for a sentence or clause of a sentence.
4. It often begins a sentence, when a personal pronoun, or the name of a person, or a masculine noun follows. It is I: be not afraid. It was Judas who betrayed Christ. When a question is asked, it follows the verb; as, who was it that betrayed Christ ?
5. It is used also for the state of a person or affair. How is it with our general ? Shak.
6. It is used after intransitive verbs very indefinitely and sometimes ludicrously, but rarely in an elevated style. If Abraham brought all with him, it is not probable he meant to walk it back for his pleasure. Ralegh. The Lacedemonians, at the straits of Thermopylae, when their arms failed them, fought it out with their nails and teeth. Dryden. Whether the charmer sinner it, or saint it. Pope.