Those “Best by,” “Use by” and “Sell before” dates stamped on the food we buy can be a source of continued confusion for consumers.Earlier this year, Congressional efforts to clarify reliable expiration dates only highlighted the problem.(This is particularly interesting to see and shows that shearing or cracking-off wasn't always used or necessary.) The mold boy then removes the bottle from the mold with tongs while the gaffer knocks off the residual glass from the end of the blowpipe and then moves back to the glass pot/tank to make another gather.
There are several different type pontil marks, all of which are a mark or scar on the bottle base left by a type of pontil rod.
There is a lot variety possible within each category of pontil marks.
The 1908 image to the right was taken at the Seneca Glass Works in Morgantown, WV.
and shows a gaffer (with the blowpipe) at work with his "mold tender" boy (seated).
If you are seeking information on what type bottle you have, go to the Bottle Typing & Diagnostic Shapes page which also will lead users to additional dating information.
have any evidence of a pontil mark though the base may have a mold line(s) and/or embossing, or be totally smooth and unmarked.
A second boy looks on with (possible) admiration of the gaffer as they were the highest paid and most elite workers on the glass factory floor and among the highest paid of all skilled laborers during the 19th century (Barnett 1926).
It was also the position that glass factory boys aspired towards (Skrabec 2007).
Film clip is compliments of the Owens-Illinois Glass Company.
(Many thanks to Phil Perry, engineer with that company.) Mouth-blown utilitarian bottles have several important diagnostic characteristics which can be helpful for dating.
Their quantities would be very small in any post-1920 archeological assemblage." The following link is to an amazing early 20th century film clip of a mouth-blown "shop" blowing bottles.