3. Whilst, however, the actions are two in number, the person or thing which does or suffers them is single--_John_. 4. _He_ (_she_ or _it_) is single _ex vi termini_. The relative expresses the _identity_ between the subjects (or objects) of the two actions. Thus _who_ = _John_, or is another name for John. 5. Things and persons that are one and the same, are of one and the same gender. The _John_ who _trusts_ is necessarily of the same gender with the _John_ who _comes_. 6. Things and persons that are one and the same, are of one and the same number. The number of _Johns_ who _trust_, is the same as the number of _Johns_ who _come_. Both these elements of concord are immutable. 7. But a third element of concord is not immutable. The person or thing that is an agent in the one part of the sentence, may be the object of an action in the other. The _John_ whom I _trust_ may _trust_ me also. Hence a. I trust John--_John_ the object. b. John trusts me--_John_ the agent. § 456. As the relative is only the antecedent in another form, it may change its case according to the construction. 1. I trust John--(2) _John_ trusts me. 2. I trust John--(2) _He_ trusts me. 3. I trust John--(2) _Who_ trusts me. 4. John trusts me--(2) I trust _John_. 5. John trusts me--(2) I trust _him_. 6. John trusts me--(2) I trust _whom_. 7. John trusts me--(2) _Whom_ I trust. 8. John--(2) _Whom_ I trust trusts me. § 457. _The books I want are here_.--This is a specimen of a true ellipsis. In all such phrases in _full_, there are _three_ essential elements. 1. The first proposition; as _the books are here_. 2. The second proposition; as _I want_. 3. The word which connects the two propositions, and without which, they naturally make separate, independent, unconnected statements. Now, although true and unequivocal ellipses are scarce, the preceding is one of the most unequivocal kind--the word which connects the two propositions being wanting. § 458. _When there are two words in a clause, each capable of being an antecedent, the relative refers to the latter._ 1. _Solomon the son of David that slew Goliah_.--This is unexceptionable. 2. _Solomon the son of David who built the temple_.--This is exceptionable. Nevertheless, it is defensible, on the supposition that _Solomon-the-son-of-David_ is a single many-worded name. * * * * * CHAPTER X. ON THE INTERROGATIVE PRONOUN. § 459. Questions are of two sorts, direct and oblique. _Direct._--Who is he? _Oblique._--Who do you say that he is? All difficulties about the cases of the interrogative pronoun may be determined by framing an answer, and observing the case of the word with which the interrogative coincides. Whatever be the case of this word will also be the case of the interrogative. DIRECT. _Qu._ _Who_ is this?--_Ans._ _I._ _Qu._ _Whose_ is this?--_Ans._ _His._ _Qu._ _Whom_ do you seek?--_Ans._ _Him._