Dating bottle glass
It was noted in 1910 that the Cumberland Glass Company (Bridgeton, NJ) had "...succeeded in perfecting a machine that will satisfactorily produce narrow neck bottles, such as catsups, beer bottles, etc., at a big saving over the hand method." The method used was unusual and may have been unique in bottle-making history: "The machine differs from all others, and in getting the neck upon the bottle, the vessel is made in two sections, the neck being put upon the bowl with a second operation. Manager says machines are fast coming into play in bottle industry, plans eventually to have machines in place of "carrying in boys." Location: Clarksburg, West Virginia" (Library of Congress).
Click on the picture to the left to view an illustration which shows both of these seams or click machine-made finish to view an image which shows well the seam below the finish.There are also no horizontal tooling marks present on the finish and/or upper neck as would be observable on the finish of mouth-blown bottles.2.