Science Art: Mouchot’s solar thermal collector from 1860, from Nordisk Familjebok, 1917.

Scientific illustration of a solar collector, a device used to capture energy (light or heat) from the Sun. Arrows show the direction of rays that bounce off angled reflectors toward a bulb that collects them, apparently heating a coil probably filled with fluid. There are no labels on this diagram.
Scientific illustration of a solar collector, a device used to capture energy (light or heat) from the Sun. Arrows show the direction of rays that bounce off angled reflectors toward a bulb that collects them, apparently heating a coil probably filled with fluid. There are no labels on this diagram.

This is a solar-powered generator. A funnel with sides angled at 90 degrees is pointed at the sun to catch its radiation, and those rays are bounced by the funnel’s mirrored walls toward a glass bulb in the center of the funnel. The bulb has a coil inside, that is, a cylindrical steam boiler. The sun’s heat warms the black-painted boiler, which generates steam, which then powers a steam engine.

It was invented by a Frenchman named Augustin Mouchot, who tested a device like this in Algeria in 1860. That collector had a diameter of about 7 feet across and generated one-ninth of one horsepower, which sort of disappointed the good monsieur. The price of coal was dropping at the time, and was so much easier to burn — what could possibly go wrong with that?

You can read more about his experiments, and the subsequent machines he inspired, at Land Art Generator, although I found the image on Wikimedia Commons and read more about the technology on Swedish Wikipedia.