Dating duraglas bottles
— but after 1940 they either added a period to indicate 1940 or two digits — 4.
Before 1940, the date digit was supposed to represent the last digit of the year — , , etc.
Cork floats could not withstand the water pressure they were being subjected to & it was difficult to obtain Spanish/Portuguese cork then.
The Owens-Illinois floats are identified by the "Duraglas" near the bottom of the float, along with an "I" inside an "O" with a diamond that is stamped on the very bottom of the float. The demand for floats began deteriorating, so the doughnut float never went in to production.
They made them by hand, rather than with machinery.
After a short period of time, they discontinued this due to the small volume needed. It is from my personal collection & one that I beachcombed on the Aleutians of Alaska several years ago.
Over 2 million of these floats were manufactured by NWG.In the early 1930's, the "Made in Germany" floats were being used off the West Coast of the United States by American fishermen.