X marks the spot

The R symbol is well known as the sign of a prescription, and it is often said that it is R_x, a shortened version of the Latin word recipe, take. But R is not R plus x; it is a corruption of a symbol that was once used by the ancient Egyptians to signify the utchat, the eye of Horus.

As with so many ancient gods, Horus had several manifestations, which are often confused with each other. Originally he was Horus the Elder, the falcon headed god of the sky. Other manifestations included a war god, two different forms of sun god, and various children of Isis and Osiris, also known as Harsiesis, Harpakhrad, Harpokrates, and Horus the Younger.

Horus the Elder had two eyes, the sun …