Pontil scars on dating glass

Posted by / 18-Aug-2020 09:16

Pontil scars on dating glass

Schulz does reference Frank Gessner’s 1891 written, Glassmaker’s Hand-Book, who noted, “the use of manganese has, however, been largely abandoned in European factories in latter years” – and Schulz added, “because it changed color.” The commotion of ‘sun-purpled’ glass in the glass bottle collecting world?Profiteers have discovered ways to speed up the solarizing process by artificial means—irradiated, or with the assistance of a germicidal black light.Schulz in his book, Baffle Marks and Pontil Scars: A Reader on Historic Bottle Identification.He concluded that regarding manganese use in glassmaking, “popular use seems to have begun by at least the mid 1870s and was solidly in place by 1890” and that a “practical end date for manganese use in all but specialty bottles is about 1920” but gives no definitive reason for the stoppage, though he does note that the end of manganese use generally corresponds with the end of mouth-blown bottle production.

But buyer beware: the artificial ‘purpling’ of glass usually causes a much deeper or peculiar shade as a result of strong doses of irradiation.In the column at right are a few examples of the actual embossing on various specimens describing their contents.As you can see, the catch all term "soda" has come to represent natural and artificially carbonated waters, as well as a variety of alcoholic beverages whose carbonation results from fermentation.Many collectors and historians believe that strong twine was used to tie the cork prior to the acceptance of thick metal wire closures as a standard.This supports the idea that the blob top with it's rounded bottom was designed to accept the heavy bail wire which would scrape and wear the edges of the earlier tapered tops.

pontil scars on dating glass-32pontil scars on dating glass-62pontil scars on dating glass-26

As soda forms evolved, the blob top and heavier glass became more prominent, as the transition from open to iron pontil, and then to the "snap case" progressed.