Licensed professional surveyor; latitudes and departures;

following United States instructions. All calculations to ascertain the contents of a tract of land by a licensed professional surveyor appointed by the board of county commissioners shall be made by latitudes and departures, and on each plat shall be laid down the variations of the magnetic needle from the true meridian. In reestablishing missing corners, the county surveyor shall establish said corners in strict accordance with the manual of instructions of the United States to the United States deputy surveyors.