Sometime in the mid - 1820 ’ s, he put a bitumen - coated pewter plate in a camera obscura facing a window of his estate and exposed it for eight hours.
Umbes 1820. aastate keskel pani ta pimekambri seinale asfaldiga kaetud tinapliisulamiplaadi ja valgustas seda kaheksa tundi, kusjuures pimekambri avast paistis tema hoov.