The chronovisor (or chronoscope) is allegedly a functional time viewer, an hypothetical device capable of capturing and reproducing images and sounds from the past
This episode is also available as a blog post: https://weirditaly.com/2021/10/10/the-chronovisor-a-time-machine-allegedly-invented-by-the-italian-monk-and-exorcist-pellegrino-ernetti/