Vertically cut sound records

FUNDAMENTAL advances in recording and reproducing sound have been made recently through the use of vertical undulations on a disk. These vertically cut disk sound records possess important advantages over laterally cut records, and their use has permitted both the recorder and reproducer to be greatly improved. Among the changes made are the use of “cathode sputtering” to render the original wax electrically conducting before being electroplated, instead of the previous process of graphiting the wax; and the replacing of the abrasive record of the past with a non-abrasive final record.