Lighting and Heating with Gas 1870—1930
By the late nineteenth century, gas, either natural or manufactured, was an alternative to coal and oil for heating and illuminating homes and businesses in many states. Natural gas, composed largely of methane with small amounts of hydrogen and nitrogen, was, if mixed with air, highly explosive. That was also true of manufactured gas, made by the destructive distillation of bituminous coal. It was almost pure methane.
Although natural and manufactured gas were interchangeable fuels, they differed in two important respects. Natural gas was relatively inexpensive, and it had high heat values, measured in British thermal units (Btu). By contrast, manufactured gas was expensive to make, and its heat values were low, often 50 percent, or less, of natural gas. Consequently, natural gas, if available, was preferred over manufactured gas. In Colorado, as in much of the nation prior to the second quarter of the twentieth century, natural gas was either nonexistent or in short supply. Therefore gas, if available for heating and illumination, was of the man-made variety.
Gas distilled from coal in airless retorts was first used in Europe to create a convenient fuel for illuminating streets during hours of darkness. This process was first applied in the United States in 1816 to produce gas for Baltimore's streetlamps. Later, manufactured gas was distributed through underground mains to residential and business customers in Baltimore.