In 1913, the first true stainless steel was cast in Sheffield, England. It was a steel alloy that contained 0.24% carbon and 12.8% chromium. English metallurgist, Harry Brearley was developing a more erosion-resistant steel for rifle barrels. In order to examine the grain structure of the steel he needed to etch samples with acid before examining them under the microscope. The etching reagents he used were based on nitric acid, and he found that this new steel strongly resisted chemical attack. He then exposed samples to vinegar and other food acids such as lemon juice and found the same result. Brearley realized that this new steel could also revolutionise the cutlery industry.