The different types of irony.

Verbal irony ... is a statement in which the meaning that a speaker implies differs sharply from the meaning that is ostensibly expressed. The ironic statement usually involves the explicit expression of one attitude or evaluation, but with indications in the overall speech-situation that the speaker intends a very different, and often opposite, attitude or evaluation Dramatic irony involves a situation in a play or narrative in which the audience or reader shares with the author …

…the former husband of Hester. The man one would expect to most ardently hate the Reverend is living with him and actually working hard to keep his health together. The fact that this man is a doctor of sorts and yet seems personally to be so physically unwell is ironic. Like a poor financial advisor or a mechanic that always has car troubles. Examples of irony are everywhere. Behold them in their vast literary glory!!