In 1915, Corning Glass introduced the first glass ovenware, made of a new, clear, heat-resistant material, Pyrex®. Its cooking potential was discovered in 1913 by Dr. Jesse T. Littleton of Corning when he provided his wife, Becky, with a makeshift casserole out of a cut-down Nonex battery jar. Surprisingly, it survived the oven as well as traditional ceramic casseroles. After Corning revised the original Nonex formula to remove the lead (dangerous in food products), the ovenware was successfully tested by Sarah Tyson Rorer, Director of the Philadelphia Cooking School and culinary editor of the Ladies Home Journal. The first product produced was a circular nine-inch "pie" plate (some say leading to the name"pie-rex"). Others say the name Pyrex was a technical derivative of the Greek "pyra" (for hearth), and the "ex" ending which had valuable brand-name similarity to Nonex. But what was Nonex? It was a "low-expansion" glass developed in 1908 by Dr. Eugene Sullivan, the first Director of Research at Corning Glass Works (founded 1851), to reduce product breakage. As a doctoral student in Leipzig, Germany in 1900, he had learned of experiments using borosilicate glass at the Jena Glass Works by Dr. Otto Schott, and applied this knowledge. The glass was used in weather shock-resistant lantern globes, and battery jars called Corning Nonex (for non-expansion). The same year Pyrex was introduced, a coffeemaker using it was marketed, using the "Silex" vacuum-drip principle. The name "Silex" was explained: "Sanitary and Interesting method of making Lucious coffee. It is Easy to operate on account of its being X-ray transparent." The design had originated in Europe, and rights were obtained in 1909 by two sisters, Mrs. Ann Bridges and Mrs. Sutton of Massachusetts, who had it manufactured by the Frank E. Wolcott Mfg. Co.