"We ride nonpolluting bicycles to save mankind, but we lock them because we can't trust mankind."
Unknown
In 1206 an Arab scholar, AI-Jazari, published a book called Kitab fi ma'rifat al-hiyal al-handasiyya (Book of Knowledge of Ingenious Mechanical Devices). The little- known academic described numerous devices that had not yet been invented, including the waterwheel, the crankshaft, and the combination lock.
In 1550 an eccentric Italian mathematician expanded on AI-Jazari's early ideas and produced what is now recognized as the first combination lock. Gerolamo Cardano (1501-1576), notoriously short of money, kept himself financially afloat through successful gambling and chess playing. But he was also a notable inventor and produced a practical product to help keep possessions secure.
Cardano's design used a number of rotating discs with notches cut into them. The lock could be secured by a pin with several teeth that hooked into the rotating discs. When the notches in the discs came into alignment with the teeth on the pin, the lock could be opened.
Today, Cardano's combination lock is considered to be one of the least secure types because, if not machined precisely, it can be opened without knowledge of the correct combination. An open lock can be achieved in very little time simply by rotating the discs and listening for the clicks indicating that the tooth has settled into its corresponding notch.
Cardano's original design is still used for low- security bicycle locks and briefcases, but now it must compete with sophisticated electronic combination locks whose codes are not cracked so easily.
