The testimony of a witness taken upon interrogatories, not in open court, but in pursuance of a commission to take testimony issued by a court, or under a general law on the subject, and reduced to writing and duly authenticated, aud intend-ed to he used upon the trial of an action in court. Lutcher v. U. S., 72 Fed. 972, 19 C. C. A. 259; Indianapolis water Co. v. Amer-tcan Strawboard Co. (C. C.) 65 Fed. 535