(1) Whenever, in the course of a trial referred to in section 40, the evidence of any witness is required in relation to the subject -matter, any deposition previously made by him in relation, to the same subject-matter before any Court making an investigation under this Chapter shall, if authenticated by the signature of the Magistrate or presiding Judge of such Court, be admissible in evidence on proof —
(a) that the witness cannot be found within the jurisdiction of the Court before which the trial is held; and
(b) that the deposition was made in the presence of the person accused, and that he had an opportunity of cross-examining the witness.
(2) A certificate signed by such Magistrate or presiding Judge that the deposition was made in the presence of the accused, and that he had an opportunity of cross-examining the witness shall, unless the contrary be proved, be sufficient evidence that it was so made and that the accused had such opportunity.