Historians estimate that in 1800 all of the steam engines in Britain could generate perhaps 50,000 horsepower. By 1870 the figure had soared to more than 1.3 million horsepower, a twenty-six-fold increase. Nobody was going to wait for solar enthusiasts to fiddle with mirrors that didn't work on rainy days. Mouchot was trying to persuade society to switch from a stable stock of coal to an inconstant flow of sunlight. And society was not terribly interested.