That conception is still with us today in the disk record. To avoid spreading time over miles and miles of groove length, that groove was from the beginning reduced to a circular path, as one confines hundreds of yards of string to a ball and miles of wire to a reel. Only later did the spiral wind in upon itself on the surface of a disk. It's a good idea, at this stage, to fasten upon this conception of the recording of time itself, and separate it from the recording of sound patterns. Time recording comes first.
Time is limited by length, extended by more length-one dimension in terms of another.
Lateral and Vertical Recording Introduce sound itself upon this rigidly controlled time recording, and we have a new and more diverse element. The grooves of all types of groove recording are basically the same. But with sound waves to be translated into actual physical motion of the stylus which cuts the groove, divergencies of method appear at once. The half-mile groove is no longer perfectly even but preserves in its sinuosity the pattern of the stylus movement. The Two Silent Dimensions Take a good look at these grooves.