There was a kind of fog that was not formed because the weather was cold enough for moisture in the air to condense, but because water had been heated into steam.
Steam had been regarded as a potential source of energy since the first century. On Christmas Day in 1801, Richard Trevithick built the first high-pressure steam locomotive, the Puffing Devil. On its first run, it successfully pulled a full-sized steam road carriage; on its second run three days later, it was scrapped because the engine overheated.
High pressure raised the temperature at which water evaporated, from 100 degrees Celsius to 110 degrees or even higher. Food never cooked properly at high altitudes because low air pressure made water boil below 100 degrees Celsius. At such times, one needed a pressure cooker to assist with cooking, or simply roast the food directly over a fire.
A steam boiler had to exceed water's normal boiling point of 100 degrees Celsius under atmospheric pressure in order to generate power. Once the steam drove the piston, the depressurized exhaust had to be released while fresh high-pressure steam entered, beginning the next work cycle.
The factor preventing steam locomotives from replacing horses was the problem of cooling. Britain was unquestionably the authority on the railway industry. The tracks used for horse-drawn railways differed in width from those for steam trains; the latter were much wider, required sleepers, and needed a proper roadbed. This made French bureaucrats cautious about laying railway networks across large areas.
By comparison, the Austrians had become far more open-minded. Budweis in Bohemia was a world-famous beer town. They intended to build a horse-drawn railway linking Linz and Budweis, then extend it to the saltworks near the spa town of Gmunden.
Who knew when the English would finally develop a steam