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(Note: the term "parison mold" and "blank mold" are synonymous for the first mold in the two mold machine process.): (see the Note box below point #3 for an exception) run up to the highest point of the finish and often onto the extreme top finish surface (i.e., onto the rim or lip).On many early (very early 1900s into the 1920s) and occasional later (1930s and later) machine-made bottles the vertical body/neck and finish mold seams are discontinuous and offset from each other; click offset seams for a picture of this attribute.: There are a few machine-made bottle types (milk, shoe polish and small ink bottles) or post-production processes (fire polishing) which exhibit mold seams in the finish/upper neck that deviate from the descriptions in points #1 and/or #3 above; these bottles may appear to be of mouth-blown manufacture.
Feature #7 describes a couple glass related features that are quite consistent in machine-made bottles, but not diagnostic, i.e., mouth-blown bottles may sometimes have few/no bubbles in the glass and even thickness.This mark is distinctive to the suction process which feeds glass into the bottom of an Owens machine's parison mold.(Note: A movie clip showing this process in action is linked at the bottom of this box.) Suction scars can not be produced by feed and flow automatic machines (i.e.General Machine-made Diagnostic Features: Machine-made bottles will exhibit most or all of the diagnostic characteristics explained and illustrated below.(This summary is largely an amalgam of Toulouse 1969b; Miller & Sullivan 1981; Jones & Sullivan 1989; Boow 1991; Cable 1999; Miller & Mc Nichol 2002; Miller & Morin 2004; empirical observations.) It should be noted that features #1, #3, #4, #5, and #6 are primary indicators of machine-made manufacture.In any event, the suction scar is found on mouth-blown bottles though suction scars are sometimes referred to as a pontil scar by the unfamiliar.See the machine-made section of the Bottle Bases page for more information on these scars. with distinct suction scars were likely Owens machine produced.)6. Machine-made bottles tend to have few if any bubbles in the glass and the thickness of the glass is usually more uniform throughout the bottle as compared to mouth-blown bottles.Most machine-made bottles have mold seams about the thickness of a hair while most visible mouth-blown mold seams tend to be several times as thick, higher, but more rounded.(Mold seam thickness and how high it protrudes [height] is of only moderate use in telling a machine-made bottle from a mouth-blown bottle, though if a bottle fragment has a hair fine mold seam, it is highly likely to be from a machine-made bottle.) 3.Though patented and first used to a limited degree in 1903, the first Owens Automatic Bottle Machine licenses were granted to other manufacturers in late 1904 making 1905 the effective "beginning" (i.e., terminus post quem) date for bottles with all of the above listed machine made diagnostic characteristics (Miller & Mc Nichol 2002).Bottles which have all the primary characteristics noted above (#1, #3, #4) bottles.