Exactly what these Diagnostic Keeps Indicate: Bottles using noted top machine-made services (#1, #3-#5)
including the suction scar on the base (point #5 above and picture to the left) can date no earlier than 1905 and are usually post-1910. 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 & McNichol 2002). Bottles which have all the primary characteristics noted above (#1, #3, #4) versus the suction scar (#5) were produced by non-Owens automatic or semi-automatic machines and are somewhat harder to precisely date, though the vast majority post-date 1905 also.
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