Sundial cartoon. A sundial is a solar powered clock
In the cartoon a person is looking at a sundial and is saying “It’s incredible that all those years ago they’d developed solar-powered clocks.”
The cartoon illustrated how in the modern world we assume everything has to be powered by a relatively modern form of power, such as electricity in the form of batteries or mains electricity. In the past everything was powered by “sustainable” or “natural” resources, such as solar power, the wind or water.
A cartoon about the history of clocks, horology