As one might expect not only does Hero hardly mention the manufacturing process in the text of his treatise, he never explains how to construct any part of the machine, no matter how critical.
By contrast, al-Jazari’s text and illustrations represent the growing importance and status of mechanical arts in the Middle Ages as well as their association with the most sweeping kinds of earthly, philosophical, and cosmological order.
Developed from French regency bracket clocks, they adorned the numerous fireplaces of royal palaces and wealthy manor homes.
Frequently made from brass, these clocks featured intricate embellishments and detailing and were sometimes accompanied with candleholders or vases.
England was behind by a few years but the first shelf clocks came in the form of lantern clocks and then bracket clocks featuring both brass and wood cases.
A valuable recent article by Aiken on the impact of Al-Jazari (fl. The ingenious complexity of his devices, as well as his desire to instruct followers in the art and science of making them, Aiken points out, compelled al-Jazari to provide more detailed written descriptions of their inner workings than those found in any known older treatise.
The instructive value of al-Jazari’s innovative drawings are obvious when compared to the typically more abbreviated illustrations found in a 13th century copy of Hero of Alexandria’s Pneumatica of the first century.
Clepsydra refers to a water clock (its Greek translation is “water thief”) which measures time by regulating the flow of liquid from one vessel to another.
In 807, Emperor Charlemagne was sent a brass clock by the Abbasid caliph, Harun al-Rashid in Baghdad.