Johnson - Wonderland: how play made the modern world

An illustration of a life-sized elephant clock, from al-Jazaris The Book of Knowledge and Ingenious Mechanisms

More significant, though, than the elegance of Baghdads broad avenues and lavish gardens was the scholarship sustained inside the Round Citys walls. Al-Mansur founded a palace library to support scholars and funded the translation into Arabic of science, mathematics, and engineering texts originally written in the days of classical Greeceworks by Plato, Aristotle, Ptolemy, Hippocrates, and Euclidalong with Hindu texts from India that contained important advances in trigonometry and astronomy. (These translations eventually turned out to be a kind of lifeboat for these ancient ideas, keeping them in circulation through the European Dark Ages.) A few decades later, under the leadership of al-Mansurs son, al-Manum, a new institution took root inside Baghdads walls, a mix of library, scientific academy, and translation bureau. It became known as Bayt al-Hikma: the House of Wisdom. For three hundred years, it was the seat of Islamic scholarship, until the Mongols sacked Baghdad in the siege of 1258, destroying the books from the House of Wisdom by submerging them in the Tigris.

In the first years of the House of Wisdom, al-Manum commissioned three talented brothers, now known as the Banu Musa, to write a book describing classical engineering designs inherited from the Greeks. As the project evolved, the Banu Musa expanded their brief to include their own designs, showcasing the advances in mechanics and hydraulics that surrounded them in Baghdads flourishing intellectual culture. The work they eventually published, The Book ofIngenious Devices, now reads like a prophesy of future engineering tools: crankshafts, twin-cylinder pumps with suction, conical valves employed as in-line componentsmechanical parts centuries ahead of their time, all represented in detailed schematics. Two centuries later, the Banu Musas work inspired an even more astonishing project, written and illustrated by the Islamic engineer al-Jazari, The Book of the Knowledge of IngeniousMechanisms. It contained stunning illustrations, adorned with gold leaf, of hundreds of machines, with careful notes explaining their operational principles. Float valves that prefigure the design of modern toilets, flow regulators that would eventually be used in hydroelectric dams and internal combustion engines, water clocks more accurate than anything Europe would see for four hundred years. The two books contain some of the earliest sketches of technology that would become essential components in the industrial age, enabling everything from assembly-line robots to thermostats to steam engines to the control of jet airplanes.