Another method of dating bottles is by looking at their colour. From the late 1800’s until 1915, manganese oxide was added to raw materials used to make glass. The use of the mineral produced a clear glass. However, when exposed to sunlight, the sun’s UV rays turn the glass purple or amethyst.
From 1916 to 1930 selenium oxide was used instead. This glass, too, will change colour when exposed to sunlight but turns a pale yellow rather than amethyst.
After 1930 arsenic was used to manufacture clear glass. Some bottles have embossed or raised lettering on them, making identification easy. One bottle from my grandmother’s collection was labeled “St. Jakob’s Oel (Oil). I found a similar example on a website of South African bottles. The oil was touted as a cure for arthritis and the company manufacturing it began advertising it in 1858.
I still don’t consider myself a collector and doubt I’ll go out and dig like I did when I was a child but I do continue to watch for unusual bottles. They can turn up anywhere from old sheds, to yard sales and auctions or even basements. They are out there, just waiting to be found.
(February 27, 2007)
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