A few books from the Middle Ages can tell us more about these magic tricks, such as the Secretum philosophorum, which was written by anonymous author at the beginning of the fourteenth-century.

At the beginning it explains “there are contained in it certain secrets which, by vulgar opinion, are impossible, but which philosophers consider to be necessary and secrets. Now, contained in this book are the secrets of all the arts.”

While the Secretum philosophorum might sound to be very mysterious, a modern reader might find it to be more a medieval version of The Dangerous Book for Boys – it contains all sorts of fun stuff, like how to make different colors of ink, riddles, and creating scientific experiments like how to make a soap bubble.

Some of the tricks:

• To Give Water the Colour and Taste of Wine
• To make a burning mirror
• To free hands tied behind the back
• So that cooked meat will appear to be full of worms
• So that someone may appear to burn, but nothing is in fact generated except terror
• To make invisible ink

Via Medievalists.net for details on the tricks as described in period as well as more information on the primary sources.