Justin Pollard & Howard Reid: From ‘The Rise & Fall Of Alexandria’ – The Curse Of Hero Of Alexandria
‘Pharos of Alexandria’, circa 250 C.E., constructed by Sostratus of Cnidus.
Picture from the Mary Evens Library
Today’s sharing from the Blue House of Via-HYGEIA is from Justin Pollard & Howard Reid’s ‘The rise & fall of Alexandria’, Penguin Books_2006, excerpted from chapter 12, ‘The Clockwork City’.
…’In Fact, in Alexandria in the first century AD, Hero was the greatest of the wonder-workers. He was a designer and builder of automatons-automatically operated machines-with which he delighted and bemused the people of the city. The machines he built used gravity, pressure, heat, and water to power devices that appeared to operate without human intervention. They would have surprised and bewildered an eighteenth-century European as much as they did Romans and Alexandrians. In his great book, the ‘Pneumatica’, he explains the purpose of his life:
‘By the union of air, earth, fire and water, and the concurrence of three or four elementary principles, various combinations are effected, some of which supply the most pressing wants of human life, while others produce amazement and alarm’. Hero of Alexandria, ‘Pneumatica’, introduction.’
‘…The machines that Hero built were wonders of their age-indeed, they would have been the wonder of many ages since-and their deployment about the city made it appear to visitors to be literally a place of miracles. Some were for the home, simply there as entertainment for dinner parties. Others, whirred and clanked away in theaters, producing amazing special effects. But the most likely place to find one of Hero’s machines was where magic and miracles were only to be expected-in the temples.’
‘Hero could build devices which appeared to perform tasks either without human assistance or through divine intervention. It was the stage magic of its day, utilizing hidden machinery to make and audience stop in the street and look in awe at the show being put on by whichever god was worshiped in the temple where Hero had installed his device.’
…‘For the Alexandrians of his day, Hero was not a mechanical genius but just another in a long line of toy makers, a gadgeteer. It was this attitude that would lead people to overlook perhaps his greatest invention, one that would eventually change the world forever. Tucked away in his surviving notes lies his plans for an aeliopile. He described this novelty toy as two copper tubes soldered to the top of a sealed metal container. These passed through two metal sleeves leading into each side of a copper sphere that could rotate between them. From the sphere emerged two outlets facing opposite each other. When water was boiled in the lower sealed compartment, steam would shoot out of the outlets, making the ball spin around, to the delight of the audience. And they should have been delighted and amazed. Spinning at around 1500 rpm, this was the fastest man-made rotating object in the ancient world. But it much more than that. It was the first use of jet power. And more amazing still, it was, of course, a prototype steam engine. Had Hero combined this toy with the piston-something his fellow Alexandrian Ctesibius had invented some three hundred years before-he could have created a working steam engine; but tellingly, he didn’t.’
‘…There were fundamental problems with his aeliopile design that certainly didn’t help. The main problem with it was its efficiency, or lack thereof. To allow the ball to spin freely the joints had to be made quite loose, but if the joints were loose then a lot of steam escaped through them. Then there was the problem of fuel. In the Roman world the boiler would have to be powered by wood, and that would have to be collected by someone-probably a slave. So if the useful energy gained from burning the wood to make the steam to turn the ball was less than the energy used by the slaves to collect the wood, then the efficacy of the device would be lost and the slave might as well be told to do the work himself. But it is not just efficiency that worked against Hero’s steam engine. Those very slaves who would be needed to collect the fuel were themselves an obstacle to there ever being a Roman industrial revolution.
The main use of steam engine during our industrial revolution was for producing cheap and readily available power. Hiring people to do jobs by hand was expensive, and it was sometimes difficult to get skilled people when you needed them. Steam engines could work day and night without rest, they were always available, and they were strong. The Roman already had a source of cheap and plentiful labor in the form of slaves, and the Ptolemaic administration was particularly well suited to their use. If machines had replaced slaves, where would the slaves have gone? No one wanted another Spartacus. For an elite whose wealth was based on land, such a device simply wasn’t in their interests.
And so Hero’s greatest invention was condemned to be no more than a party novelty, just another description of a marvelous engine in a book in the vast Alexandrian library. The Romans had no real need for his work, so their interest in the contents of the world’s greatest library lay not in the abstractions of Plato and Aristotle or in Hero’s experimental physics. They were interested in the construction of siege engine and artillery, in the laying out of roads and cities, in harvesting the vast resources of their new conquests. The mechanical delights of wine dispensers and antikythera mechanisms had their place, but a machine that undermined the whole base of their society-slavery-certainly did not.’
Many themes, events and circumstances
in this sharing sound sadly familiar, don’t they? 😔