Hi Gary .. while Forum was down I did a bit of snooping. Couldn't recall which mag you wanted and discovered both Popular Mechanics and Popular Science are online back to the 1800's on Popular Science and 1902 for Popular Mechanic's. Anyone can view the mags page by page online for free or download. Looked at a few of both for 1950 and 51 but didn't see the De Vaux. Don't know if there is a way to pinpoint the item.
At least there are only 4 PM a year and 300 odd pages per mag. All you do is click on the cover of year and it will give you the 4 mags that year.
Just hit me, another senior moment of many, wonder if either mag carried ads / info for our cars 1921 to 1934. Not sure Durant Motors put ads in mags as I didn't see any in the few Sat Evening Posts I have from 1900 to 30's or the odd PM I have late 20's. Dandy full page ads in colour on other vehicles in SEP and smaller black / white ones. Got a kick of black / white on cars 1900 to 1904 in SEP.