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Age of Invention: The Spanish Engine
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A couple of weeks ago, when I shared my post about the invention of the steam engine, I noticed a few people on social media responding that the steam engine had, in fact, been invented in Spain — almost a hundred years before Newcomen was tinkering with his engines in Cornwall in the 1700s. I had not heard this claim before, so decided to look into it.
The Spanish claimant in question is one Jerónimo de Ayanz y Beaumont, a late-sixteenth-century aristocrat and military engineer from Navarre, who from 1597 served as the administrator of the royal mines, and who invented a whole host of devices, from diving equipment and mine ventilation systems, to various improvements to mills, pumps, and furnaces. Thanks to the work of historian and engineer Nicolás García Tapia, whose biography of Ayanz came out in 2010, we now know quite a bit about this interesting inventor. The work was published in Spanish, and quite understandably was widely covered in the Spanish press. So although Ayanz has not quite become a household name in Spain just yet, he does now seem to be fairly well-known by the local “well actually” brigade (a shadowy international movement of which I am, to most people’s annoyance, a long-serving member). “Thomas Newcomen/Thomas Savery invented the steam engine you say? Well actually, I think you’ll find it was Ayanz a century earlier” — I had a quick google and discovered there were hundreds of comments to this effect.
But, actually, the story is a bit more complicated than that. The devil, as always, is in the detail, and unfortunately the press claims about the technology have become widely and erroneously repeated, apparently ignoring Tapia’s careful historical work. I even spotted a recently-published encyclopaedia of inventions that repeated the errors.
So what, exactly, did Ayanz invent? The key fact is that in 1606 he obtained a 20-year monopoly from the king of Spain for the use of over fifty different inventions, including two steam-related devices. One of these was related to getting rid of deadly mine gases, which had killed one of his friends and collaborators, and had almost killed Ayanz too. His solution was a steam injector — essentially, a steam boiler with a narrowing pipe sticking out of it, which would inject the steam into a larger air pipe. The pressurised steam, upon flowing up into the air pipe, created a powerful sucking effect behind it, thus rapidly drawing deadly gases out of the mine. (A bit like at the start of this video).
It was the second steam-powered device, however, that has become famous as Ayanz’s steam engine. Just like the inventions of Thomas Savery and Thomas Newcomen about a century later, it was designed to pump the water out of mines. Ayanz formed a partnership in 1608-11 to reopen the silver mines of Guadalcanal in Spain, which had been abandoned due to flooding, and seems to have tried to implement the engine there: he obtained rights to cut down nearby trees for firewood, for example, and exploited nearby copper, which would have been essential for making boilers and pipes. As for whether he actually got it to work, we don’t know for sure. Sadly, he died only a few years after starting the project.
But the devilish detail is in how his engine worked. Specifically, all the multiplying errors seem to have arisen from a misinterpretation, by the press, of Tapia’s statement that the engine was “very similar” to that of Thomas Savery. There are, certainly, some important similarities. Both engines, for example, exploited the expansionary force of steam. In both, steam from a boiler was piped into a water tank, forcing that water up a narrow pipe — what we might call a pushing effect. And both engines used two tanks, which alternated so that the engine would pump continuously. While one tank was being refilled with mine water, the other would be have the steam pushing the water out, and then vice versa. So far so good. Indeed, due to the two water tanks, drawings of Ayanz’s and Savery’s devices look very similar side by side.
But that is where the similarity ends (which Tapia actually makes clear, if people had read him carefully). As I mentioned a few weeks ago, the steam engines invented by Savery and then Newcomen in the 1690s and 1700s mainly exploited the observation that the air had a weight — the main force was applied, not by the steam itself doing the pushing, but by the steam within a tank being doused in cold water, causing it to rapidly condense. The resulting partial vacuum meant that it was the weight of the air — the atmospheric pressure — that did the real lifting work. Rather than using hot steam to push, these engines used its condensation to suck.
For Newcomen, this pulling effect happened under a piston in a cylinder, with the piston driving a beam up and down, which in turn worked a pump all the way down the mine. But Savery’s engine exploited the sucking effect to do the mine pumping directly. (By the way, Savery’s engine seems to be very poorly understood by the public, especially compared to Newcomen’s. I wonder if this has also contributed to the misunderstanding of Ayanz’s and Savery’s relative achievements. There are a few Youtube videos claiming to show how Savery’s engine works, but almost all of them are completely wrong. This is the only accurate one I could find.) Savery’s engines were supposed to be placed down inside the mine itself, and did not use any pistons. Instead, steam would be admitted to a tank, which would then be doused in cold water. The resulting condensation meant that the mine water itself was sucked up into the tank, and only then, like Ayanz’s engine, would the steam be admitted into the tank again to push the water up and out of the mine via a thin pipe.
Thus, Savery exploited both the pushing and pulling power of steam, with one of the tanks admitting steam while the other was being condensed. Ayanz’s machine, on the other hand, only exploited the pushing. In Ayanz’s machine, the tanks only received water by being below the level of the mine water that was being drained, not through any kind of suction. Savery’s, on the other hand, could suck water into the tanks to a height of up to 8 metres. Indeed, Tapia is unequivocally clear on this difference. Ayanz, he writes, “did not contemplate the possibility of utilizing a supplementary source of pressure — that of the atmosphere”.
And nor could he have, for Ayanz was tinkering with steam devices decades before atmospheric pressure was sufficiently understood. It’s a very clear case of how the lack of science limited the technological possibilities. Indeed, even Savery’s machine, despite its greater sophistication, proved to be a technological dead-end. It was at one stage used for London’s water supply, to pump water from the Thames, but without much success. And it was impossible in mines, due to the physical limits to how high it could raise the water. The sucking effect was limited by the weight of the air — hence the achievable maximum of about 8 metres — and the pushing effect had all sorts of other problems. Increasing the steam’s pushing force required one of two methods: either increasing its pressure, or, as Ayanz tried, having a chain of water tanks at different storeys, one filling into the next one up, but each pushed by the same low pressure. Yet both methods were completely impractical, at least at the time. Increasing the pressure typically strained and broke the pipes and boilers, while Ayanz’s method would have required huge amounts of fuel to produce sufficient steam. Savery hoped to have multiple engines at different stages of the mine, one pumping up to the next, but that would also have been impossibly costly in terms of fuel and maintenance too (not to mention dangerous, having so many engines underground).
Ultimately, Newcomen achieved the breakthrough by applying the science of vacuums in a much more elegant and practical way than Savery did — but at least Savery was on the right track. He had the benefit of understanding the nature of air, whereas Ayanz, by being too early, could not. Ayanz may have invented a steam engine, but he did not invent the atmospheric engine.
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