The execution of an instrument may be established by proof of the handwriting of the party and of a subscribing witness, if there is one, in the following cases:
1. When the parties and all the subscribing witnesses are dead;
2. When the parties and all the subscribing witnesses are nonresidents of the state;
3. When the place of their residence is unknown to the party desiring the proof and cannot be ascertained by the exercise of due diligence;
4. When the subscribing witness is concealed, or cannot be found by the officer by the exercise of due diligence in attempting to serve a subpoena or attachment; or 5. In case of the continued failure or refusal of the witness to testify for the space of one hour after the witness's appearance.