John Dee’s Claude Glass
[Thought to have once belonged to John Dee (1527-1609), this object is a “Claude glass:” a convex piece of glass with a black blacking. They were popular among artists and tourists to look at landscapes (with their backs to the subject). Dee is said to have used this object like a crystal ball for divination (telling the future or fortunes) or scrying (seeing visions).]

Pasted from <http://www.sciencemuseum.org.uk/broughttolife/objects/display?id=10722&keywords=dee>

Pasted from <https://www.rcplondon.ac.uk/news/mystical-objects-john-dee>