This will be noted where known

Dating antique glass bottles

This, and no mold seams, is another indication of a hand-blown bottle. Newman's key made a noble attempt at simplifying bottle dating, but is weakened by the fact that the subject is much too complex to be conducive to such a simple approach by itself. Many identical shapes persisted through time and others were brought back for nostalgia and made common again. For a broader discussion of this subject see Lockhart, et al. The base of the second bottle whose lip was shown above right is displayed here.

We can always have some indication of a starting date for a technique if we can find who first put the idea into practice. No material may be copied for commercial purposes. Published works generally cover either a particular city, region, or category of bottles.

Both of these medicine bottlesFrom this shoulder seam are

But the process was completed in a single blow. If your bottle is American and has a patent number, check out this Table of U. Vertical side mold seam on the neck of a beer bottle ending well below the finish, indicating that it was at least partially handmade - ca. Fire Polishing - Occasionally encountered machine-made bottles may have fire polished finish rims - a process which eradicated evidence of the neck-ring mold seam on the rim of the bottle.

This will be shallower, wider and more perfectly circular than a pontil mark. This is the base of the bottle whose lip is shown above left. The side mold seam does not extend onto the top surface of the finish, i. Blown-in-mold bottles without pontil marks date circa s to s. In short, there was and is nothing to stop a glassmaker from using an obsolete method in the production of a bottle.

From this shoulder seam are two side seams that run up the neck and end below the top of the lip. Both of these medicine bottles look much like their earlier counterparts. The pressure from the automatic machine was strong and the molds fit tight leaving only a very thin line. The Owens machine revolutionized the bottle industry. This is another indication of a machine-made bottle.

Inside the Owens ring are several numbers. The disk-like mark is sometimes confused with a pontil. This bottle is probably free-blown or dip molded. Produced during the era where all bottles were an relatively rare and cherished commodity to be discarded only when broken i. Can usually tell that lip is crude and was applied by hand.