Assertion: disc's sound | /r/HasProperty | recorded as spiral
Facets:
value: on a disc
type: LOCATION
Source sentences:
text: Edison's early patents show that he was aware that sound could be recorded as a spiral on a disc, but Edison concentrated his efforts on cylinders, since the groove on the outside of a rotating cylinder provides a constant velocity to the stylus in the groove, which Edison considered more "scientifically correct".