Tuesday, February 23, 2010

The multi talented Hero of Alexandria

The multi talented Hero of Alexandria was a mechanic, mathematician and scientist and whose inventions inspired every one from Leonardo de Veinci. 19th century scientists were astonished to find that his mysterious inventor from classical antiquity had even built a working steam engine,

He is said to have invented screw lathe – a machine for cutting screws as well as the fly press, the fire extinguisher pump and the water clock. He is also said to have constructed a position sensor that corresponds to our modern odometer. When construction his pain staking designed instruments, this craftsman made use of all mechanical aids at his disposal- for example pistons and cam shafts. Despite these impressive achievements, hero of Alexandria, one of the most important inventors of classical antiquity, remains virtually unknown today.

For centuries it was even unclear when he had actually lived. Now days, how ever, Historians are almost certain Hero was lived in the first Century AD. For many years he was dismissed as little more than a dabbler of humble origins, and it was speculated that he might even have earned his living as a shoe maker. But the discovery, during the 19th century one of his manuscripts, The Metrica, completely transformed Hero’s image. He became recognized as an out standing mathematician and a physicist of the highest caliber, as competent in the field of hydraulics as he was in astronomy. It is possible that he taught natural science in one of the most significant school of classical world, the muse ion of Alexandria in Egypt.

Fortunately for historians, Hero wrote down his work and ideas and a large part of these writings have survived intact. His seven dissertations which represent the high point of ancient Greek technology, enjoyed extraordinary degree of popularity: for example, his dissertation on pneumatics was handed down from one culture to another; in their enthusiasm for science, that was superior to their own. The Byzantines, Armaeans, Persians and Arabs copied his work. Hero’s dissertations were read diligently during the middle ages and some scientists believe that one of them may have provided inspirations for the famed Renaissance Painter, inventor and thinker Le onardo davinci.

Hero’s greatest invention was his famous steam machine, which the Greeks called Aiolpyle. On the basis of the descriptions provided by Hero, the English classicist John Landels reconstructed the device several years ago. The main features of the Aiolipyle are a rotation water filled ball fitted with two small pipes facing one another. When the water is heated steam forms and escapes through the pipes, the resulting forces cause the ball to spin on its axis attaining a speed of 1500rpm.

By the standards of modern technology, Hero’s celebrated steam engine is very inefficient, due to its excessive friction and loss of heat. In order for the machine to give the same performance as the muscle power of man, Landels calculated that it would have to burn several hundred kilograms of wood for several hours without coal, without cast iron and with out gaskets and valves the Greeks had no chance of mastering the force of steam. Hero’s ball was probably little more than a toy; but the Alexandrian inventers brilliant gifts deserve our admiration even today

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