Back in the bad-old-days, before wide spread use of electricity, many towns had gas manufacturing plants which produced illuminating gas or town gas. The gas was produced by heating coal to generate carbon monoxide. Then steam was injected into the hot coals to break the water molecule, and yield hydrogen gas. This is the water gas shift reaction:http://en.wikipedia.org/wiki/Water_gas_shift_reaction
I'm guessing, that old-timers recalled water was added to coal, but knew not why. The chemistry of the water gas shift reaction would not have been commonly known.
Off topic a:
The Otto cycle engines were invented about the time of town gas. Some of the engines using slide valve, flame ignition rely upon the flame characteristics of a hydrogen rich gas, and will only run on hydrogen. If you look behind the buildings at an engine museum, there will be a manifold of compressed hydrogen gas cylinders.
Off topic b:
Town gas was a real improvement in the home, when used for cooking, compared to a solid fuel cook stove. This is the origin of the phrase, "Now you're cooking with gas!"
Off topic c:
The down side of town gas was its high concentration of carbon monoxide. A good way to commit suicide was to put your head in the oven and breath the gas. With today's natural gas, suicide by oven is pretty uncommon.