Philip Pullman's The Amber Spyglass As Imperial Metaphor

Philip Pullman's golden compass, subtle knife and amber spyglass (in His Dark Materials) all have an imperial nostalgic ring about them. The settings and storylines echo with the English eras of naval exploration and perhaps the Romantics - the 18th century into the early 19th.

The devices themselves are even older than that, from the Renaissance. Pullman has said, "I love the beauty of mechanical devices - orreries, watches, compasses. The alethiometer came out of my interest in the Renaissance... During the Renaisssance there was a rediscovery of Greek philosophy, and a fascination with what we now call the occult, astrology and alchemy."

Back in medieval times, the legendary Prester John had a magical mirror in which he could see every province of his kingdom.

In J.K. Rowling, on the other hand, it feels more local and national, more contemporary, Britain in the Thirties perhaps, and so we have the Pensieve, which can look into people’s memories.