One of the top vintage elegant-glass companies of the 20th century was Cambridge, which was founded in Cambridge, Ohio, in 1901. Cambridge excelled at hand-pressed, hand-molded, and hand-blown pieces, whose bases were frequently hand-finished. Extra steps made the difference. For example, after a piece was shaped, it was inserted back into a "glory hole" for fire polishing, which gave it a high gloss. In its first few decades, much Cambridge...