What glass manufacturer's mark is a P in a circle?

Answer 1

• P in a circle……….Pierce Glass Company, St. Mary's, Pennsylvania (1905-1912); Hamburg, New York (1912-1917); Port Allegany, Pennsylvania (1917-c.1980s). This factory was acquired by Indianhead Container Corporation (later merged into Ball-InCon) and is now a Saint-Gobain Containers glass plant. This mark appears on some commonly-produced medicine bottles of the early to mid-20th century, including many of the Pitcher's Castoria, Fletcher's Castoria, Dr. W. B. Caldwell's bottles and others which are found quite often in dumps of the period.