Noun
Steel made directly from cast iron, by burning out a portion of the carbon and other impurities that the latter contains, through the agency of a blast of air which is forced through the molten metal; -- so called from Sir Henry Bessemer, an English engineer, the inventor of the process.
Source: Webster's dictionaryBetween 1866 and 1877, the partners were able to license a total of 11 Bessemer steel mills. Source: Internet
It was after Bessemer steel was introduced that railroads had their highest growth rates; however, this period is usually labeled the "age of steel". Source: Internet