It is estimated that nearly 75 percent of all U.S. households own PYREX products. Just as Kleenex tissue has defined quality paper tissue and Thermos container has defined quality thermal vacuum containers, PYREX is an American product that has defined quality, heat-resistant bakeware, prepware and serveware to several generations. When asked to name a glass bakeware brand, consumers most often reply "PYREX" products. Back in the early 1900's, Corning Glass Works was working on a request from the railroads to produce lantern glass that would not break when the hot glass was struck by rain or snow. In response to this request, Corning developed globes made from low-expansion glass that could withstand the abuses of weathering and handling which readily broke the flint glass globes. Ironically, the shatterproof lantern globes generated were so good that Corning's managers witnessed a decline in sales of replacement globes. This super-tough "fire glass", as it was called, was resistant to temperature fluctuations, chemical corrosion and even breakage.