This DD, No. 52087, is the second-to-last issued Edison Diamond Disc that was recorded acoustically*. From 52089 on, they are all electrical, and no exceptions. By contrast, Victor took about a year and a half between issuing its first electrical record and its last acoustical. All the other labels had a similar transitional eclipse period. The Movies took years between "The Jazz Singer" and the last silents.
But Edison did things abruptly. They ceased issuing acoustic masters abruptly, and just as abruptly, in late October, 1929, ceased issuing records altogether! Their dealers were left high and dry. That's why so many of the Diamond Discs you find today are mint, from unsold stocks.
They picked a good time to quit the business. I used to think the Edison record company folded because of the Wall Street Crash, but actually they sold short: The very last recording made in their New York studio was on October 18th, the week before.
(BTW, I wrote this whole post so I legitimately could use the word "penultimate.")
Brad K
*52088, the very last acoustic, was by Vernon Dalhart: The Mississippi Flood / Wreck of No. 9