When what is a compound relative, you must always parse it as two words; that is, you must parse the antecedent part as a noun, and give it a case; the relative part you may analyze like any other relative, giving it a case likewise. In the first of the preceding examples, that, the antecedent part of what, is in the obj. case, governed by the verb "will try;" which, the relative part, is in the nom. case to "can be found." "I have heard what (i.e. that which, or the thing which) has been alleged."
Whoever and whosoever are also compound relatives, and should be parsed like the compound what; as, "Whoever takes that oath, is bound to enforce the laws." In this sentence, whoever is equivalent to he who, or, the man who; thus, "He who takes that oath, is bound," &c.
Who, which, and what, when used in asking questions, are called interrogative pronouns, or relatives of the interrogative kind; as, "Who is he? Which is the person? What are you doing?"
Interrogative pronouns have no antecedent; but they relate to the word or phrase which is the answer to the question, for their subsequent; as, "Whom did you see? The preceptor. What have you done? Nothing." Antecedent and subsequent are opposed to each other in signification. Antecedent means preceding, or going before; and subsequent means following, or coming after. What, when used as an interrogative, is never compound.
What, which, and that, when joined to nouns, are specifying adjectives, or adjective pronouns, in which situation they have no case, but are parsed like adjective pronouns of the demonstrative or indefinite kind; as, "Unto which promise our twelve tribes hope to come;" "What misery the vicious endure! What havock hast thou made, foul monster, sin!"
What and which, when joined to nouns in asking questions, are denominated interrogative pronominal adjectives; as, "What man is that? Which road did he take?"
What, whatever, and whatsoever, which, whichever, and whichsoever, in constructions like the following, are compound pronouns, but not compound relatives; as, "In what character Butler was admitted, is unknown; Give him what name you choose; Nature's care largely endows whatever happy man will deign to use her treasures; Let him take which course, or, whichever course he will." These sentences may be rendered thus; "That character, or, the character in which Butler was admitted, is unknown; Give him that name, or, the name which you choose; Nature's care endows that happy man who will deign, &c.; Let him take that course, or the course which he will." A compound relative necessarily includes both an antecedent and a relative. These compounds, you will notice, do not include antecedents, the first part of each word being the article the, or the adjective pronoun, that; therefore they cannot properly be denominated compound relatives.—With regard to the word ever annexed to these pronouns, it is a singular fact, that, as soon as we analyze the word to which it is subjoined, ever is entirely excluded from the sentence.
What is sometimes used as an interjection; as, "But what! is thy servant a dog, that he should do this? What! rob us of our right of suffrage, and then shut us up in dungeons!"
You have now come to the most formidable obstacle, or, if I may so speak, to the most rugged eminence in the path of grammatical science; but be not disheartened, for, if you can get safely over this, your future course will be interrupted with only here and there a gentle elevation. It will require close application, and a great deal of sober thinking, to gain a clear conception of the nature of the relative pronouns, particularly the compound relatives, which are not easily comprehended by the young learner. As this eighth lecture is a very important one, it becomes necessary for you to read it carefully four or five times over before you proceed to commit the following order. Whenever you parse, you may spread the Compendium before you, if you please.