Said abstracts, copies, minutes and extracts, or said copies thereof, if so bought as aforesaid, shall thereupon be placed in the office of the register of deeds of such county, to be copied, and arranged in such form as the county commissioners shall deem best for the public interest, and in case the originals have been lost or destroyed, or are not in the power of the party asking to use the same on any trial or other proceeding, copies of the same or any part thereof, duly certified by the register of deeds of such county, shall be admissible as evidence in all the courts in this state.