It is made the duty of the person presiding, ‘to instruct the jury upon any question of law when requested by either party; and certify to the court, with' the verdict, the substance of any decision or instruction by him given, when either party shall request it.’ R. S., c. 18, § 12. But without request he is not obliged to do it. Nor can the petitioner prove his decisions or instructions, subsequently, by calling him as a witness. The petitioner not having, at the hearing, requested the decisions or instructions given to be certified, has waived all right of exception. Exceptions overruled.