A Derbyshire priest by the name of John Hooker patented this self-divining device in 1887, but lacked the technology to make one effectively. Constructing a true mirror from two traditional silver-backed glass plate mirrors leaves a line down the middle of the image. Modern versions - consulted by image-conscious presidents and pop stars - use reflective material developed in the space race.

Self-contemplation used to be seen as a sin of sorts, especially for men. When Narcissus fell in love with his own reflection in a pool, so Greek legend has it, he was punished by being turned into the flower that now bears his name. Romans and Greeks also used discs of metal as mirrors and highly polished speculums, as they are called, can nowadays be found in reflecting telescopes.

Sixteenth-century Venetian glassmakers were the first to produce sheets of glass flat enough to be made into mirrors, which they backed with an amalgam of tin and mercury. But mirrors remained extremely expensive, and until two or three hundred years ago many people would have gone through life without ever seeing their mirror image.

The habit of mounting mirrors over fireplaces - so extravagantly displayed in the Palace of Versailles - became commonplace in the overmantels of Victorian homes, the starting point for Alice’s adventures through the looking glass. But followers of feng shui, the Chinese art of interior harmony, who regard mirrors as powerful boosters of chi, would frown on such a set-up, which projects too much fire energy into the room.

Certainly, not everything is as it seems in a mirror. Illusionists rely on them for invisible effect, some boutiques install slightly curved ones to flatter their customers, while in funfairs halls of mirrors push these distortions to ridiculous proportions. Is the mirror, as Socrates said, “a tool to know yourself” or does its two-dimensional likeness deceive us?

On reflection, what do you think?

Harvey McGavin