Nowadays, we take for granted that our oven doors and measuring cups will be see-through. But it was not always so. Normal glass will expand and shatter under the temperatures of the kitchen, so ceramics and metals were the only solution.
The magic material that changed all this was Pyrex, a borosilicate glass produced by Corning Incorporated. The heat-resistant glass was an immediate success and soon found its way into every cook's armamentarium. Oddly, its origins lie in the railway industry. Lanterns on trains would often crack because of large temperature differences between the hot lamp inside the glass and the cold weather outside. William C. Taylor and Eugene Sullivan at Coming's New York facility discovered that adding boron to the traditional glass mix improved its resilience to temperature extremes. The material was dubbed "nonex" and used with success on the railways for lanterns and telegraph battery jars. Corning went in search of other applications for the material.
Observing his wife using a nonex jar as an impromptu casserole dish, Corning scientist Jesse T. Littleton found that the glass could also withstand oven temperatures. With a little tweaking to remove lead and other undesirable chemicals to make it safe for food use, a new product line was born. Pyrex cookware went on sale in Boston in 1915, and laboratory equipment followed in the same year. The name Pyrex is somewhat arbitrary, following on the Corning affinity for the-ex suffix.
The use of this material does not end in the kitchen. Most glassware in chemical laboratories is made from Pyrex, and borosilicate glass is even used in telescope mirrors, starting with the famous Palomar Observatory in San Diego County.
