In contrast later bimal bottles will have a seam that just seems to fade away on the neck of the bottle.
top selling dating books - Pontil scars on dating glass
If you look carefully it will appear like the seam was just wiped away. Although the automatic bottle making machine (ABM) was invented in 1904 many bottle were still being made by hand for quite a few years.
By the 1920's virtually all bottles were being made by machine.
That is based on the liquid structure of glass where the atoms are held together by strong chemical bonds in a disordered and random network, To increase the stiffness of the molten glass, which in turn facilitates the process of blowing, there was a subtle change in the composition of glass.
With reference to their studies of the ancient glass assemblages from Sepphoris of Israel, Fischer and Mc Cray postulated that the concentration of natron, which acts as flux in glass, is slightly lower in blown vessels than those manufactured by casting.
There a quite a few types of pontil marks or scars but the two most common are the open pontil (O. Bottles that exhibit either one of these marks will generally date between 18.
The age of bottles dating after 1860 can be narrowed down by taking a close look at the lip of the bottle.The bowl sits on a hexagonally facet cut stem and a conical foot which measures 7.5 cm (3 inches) in diameter. The bowl is cut with an OXO border (egg and dart) and teh base of the bowl is cut with arches.The bowl sits on an extruded, vertically facet-cut stem with an embedded tear and a broad, conical foot which measures 7 cm (2.8...Stop by and visit our Antique Mall in West St Paul, Minnesota. This is a new website for us at West St Paul Antiques. I'll be working on this site over time so bear with me.It should be finished by the end of 2010 with over 500 pages at that time and 900 pages by the end of next year.If the bottle is blown into a mold with an applied lip (bimal) the seam will not go over the lip of the bottle.