- Jun 14, 2022
- Reaction score
I agree with sandchips explanation, the bottles being in the ground/privy make the lines more pronounced.They are what I call "gather lines". You'll notice on many examples that they run generally in a spiral from bottom to top and, albeit rarely, on good a example, you can see where it starts on the bottom of the bottle, which would be where the apprentice/assistant clipped the glass as the gaffer withdrew the blowpipe from the batch. When the blowpipe is inserted into the batch of molten glass, it is rotated to accumulate the desired amount of glass on the blowpipe, which is then rolled on the marver to make the gather more uniform before inserting into the mold. Some subtle change in the glass occurs during these stages that slightly changes the hardness of the glass in these areas, which sometimes becomes more pronounced after years of exposure to chemicals in the soil. I've heard them called "ground lines" but I've seen them on many, many bottles that were never buried. Hope this helps.
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