This article from the December 1922 Wireless Age is one of the earliest explanations of Charles Hoxie’s Pallophotophone electrical recording system. At this early stage it was being used to make optical sound recordings on film, but Hoxie noted that the system could easily be adapted to conventional disc recording.
The Victor Talking Machine Company experimented with the device beginning on December 8, 1922, under the supervision of in-house engineer Albertis Hewitt. After two weeks of testing, Victor management rejected it. The breakthrough for Hoxie came in 1925, when the Brunswick-Balke-Collender Company — faced with Columbia’s and Victor’s strangle-hold on the new Western Electric system — turned to the Pallophotophone (which it promptly renamed the “Light-Ray” system) out of sheer desperation. Badly flawed, it was replaced with a more conventional system in 1927, but in the meantime the Pallophotophone allowed Brunswick to compete with the new Columbia and Victor electrical recordings.
Recording the ‘Twenties (available from Mainspring Press and many major libraries) includes four chapters detailing the conversion to electrical recording.