The automatic bottle machine was much more precise in gathering an exact amount of glass and the same amount of glass for each bottle this consistency lead to more uniform products.With the uniformity, came the possibility to create a solid seal with a screw cap.Unlike most screw caps, the three point screw top had three lugs jutting out from the lip which were to engage a metal cap.This closure can be found on Whisky and medicine bottles of the 1837-1940 period.I have put up pictures of the lips so that the readers can see how they mold goes all the way over the top as shown below. This is different than an older hand tooled, hand blown bottle.
The age of bottles dating after 1860 can be narrowed down by taking a close look at the lip of the bottle.
In the neck on the right notice how just below the collar the mold seam goes complete around the neck. Both of these medicine bottles look much like their earlier counterparts.
This was the manner in which the early Owens bottles were blown. the step out collar of the example on the left is characteristic of bottles of the late teens and 1920s.
the bottle on the right appears to have a tapered collar a form which was very popular for more than 60 prior to the making of this bottle.
This is the base of the bottle whose lip is shown above left.
Beginning collectors often confuse an Owen's ring with a pontil mark and it is easy to see why this happens.