Beneath the towering ceilings of Saint-Louis’s hot glass works, there is a sense of perpetual motion. In the center of the vast hall, two monumental furnaces filled with molten crystal glow bright orange. Their contents must be kept at a blazing 1,450 degrees Celsius (2,642 degrees Fahrenheit) and stirred around the clock. One superheated cauldron holds a mass of shimmering colorless glass, while the other contains a dozen clay pots, each filled with igneous material that has been tinted with the addition of a different metal oxide: cobalt for dark blue, zinc for yellow, copper and selenium for red…. Elsewhere, workers in blue jumpsuits wield long metal tubes through which they send carefully controlled breaths into luminous, viscous knobs — while others, armed with mallets and tongs, round, stretch and…
