Further research
The earliest I could find this magnetic door mentioned was in June 1950, in which GE's ad explains how it works. As I'm posting from my cellphone, I can't get the link to the copy, but if you go to Ken's link, you can replace 1951 with 1950. The ad is in the June 19 issue of"Life".
The earliest I could find this magnetic door mentioned was in June 1950, in which GE's ad explains how it works. As I'm posting from my cellphone, I can't get the link to the copy, but if you go to Ken's link, you can replace 1951 with 1950. The ad is in the June 19 issue of"Life".