As I noted in Part I, the general idea of using heat and steam for mechanical work had a long and continuous history back to ancient times. But when we talk of the breakthrough “steam engine” in the eighteenth-century sense, we don’t mean a machine that exploits steam’s expansive, or pushing force. We actually mean a machine that does the exact opposite, exploiting the apparent sucking power that occurs when hot steam is rapidly condensed with a spray of cold water. It’s the relative weight of the atmosphere, compared to the sudden vacuum from condensing steam, that does all the work.
Fascinating as always. Thank you. A question however. In the first illustration, glass lenses are shown. Wouldn't plain glass windows have let in the same amount of heat or energy in such a setup?
Thank you! Huh, interesting question. I think I see what you mean. Perhaps by focusing on a point in the centre of the vessels it resulted in less heat loss from them? I imagine that by concentrating the rays that might also result in more conversion of the light into heat? I may need to ask a physicist...
Incidentally, de Caus's third variant was to have a frame of convex lenses to all be directed at the wall of the copper vessels rather than to be fixed within the vessel.
My thinking is this: The vessel is warmed by the sun shining of the surfaces exposed to the sun. Windows in the vessel could speed up the warming but ultimately the total energy received is limited by the area of the exposed surfaces. A lens can only collect and focus as much energy as its surface area allows. To be able to collect more energy Caus's third variant seems to collect and focus energy from multiple lenses and if these lenses have a greater surface area than the vessel, then that arrangement will achieve increased warming.
De Caus certainly used lenses, as he specifically calls them "burning mirrors" in the text accompanying his illustration. I think the best explanation is that he simply didn't understand the problem - he did not have the same, or really any, concept of energy like we do today. His third variant would have solved the problem, however: having a frame of convex lenses all directed at the wall of the copper vessels rather than in the vessel wall.
Only small technical remarks - most of described machines work by shrinking and expansion of gas (air), not by condensation. Even Savery's machine works by mixed shrinking of air and condensation.
Yes, I sometimes clarify that it's the shrinkage of air, though after the initial sucking phase e.g. in Philo's machine it seems plausible to me that there might also be some water vapour condensing there too. In general, in the parlance of the time they often frame it as a matter of "dense vs rare", and although condensation now has a very specific meaning for the actual state change, at the time they tended not to talk of steam separately, but considered it a form of air.
I did say it was Constantijn's son. But as you're now the second person to misread this, it's very clear to me that I ought to edit the phrasing to make this clearer! Which I shall do now...
Why haven't you mentioned the Worcester's water-commanding engine?
1663 description of "fire-water work" in Worcester's Century of Inventions:
“ An admirable and most forcible way to drive up water by fire; not by drawing or sucking it upwards, for that must be as the philosopher colleth it intra sphaeram activitatis, which is but at such a distance. But this way hath no bounder, if the vessel be strong enough ; for I have taken a piece of a whole cannon, whereof the end was burst, and filled it three quarters full of water, stopping and screwing up the broken end, as also the touchhole, and making a constant fire under it; within twenty-four hours it burst, and made a great crack : so that, having a way to make my vessels, so that they are strengthened by the force within them, and the one to fill after the other, I have seen the water run like a constant fountain-stream, forty feet high : one vessel of water, rarefied by fire, driveth up forty of cold water, and a man that tends the work, is but to turn two cocks, that one vessel of water being consumed, another begins to force and refill with cold water, and so successively, the fire being tended and kept constant, which the self-same person may likewise abundantly perform in the interim between the necessity ot turning the said cocks.”
Getting there! We’re up to the 1610s so far, but Part III will get to the mid-17thC. I alluded to Worcester’s machine briefly in my previous update post on perpetual motion, as being part of my investigation. It’s pretty murky though still, and I’m collecting some corroborating evidence. From that famous description you’ve quoted, it sounds like it used the expansive force of steam. But there are a few hints elsewhere about it.
The link in footnote 14 is broken.
Hmm yeah, seems to be a problem with the site, but that is the URL I used (I have a saved version of the document). Not sure what to do there!
I'll bookmark it and check back - in good news, at last one person is reading the footnotes!
Haha yes! I've only started including footnotes very recently, and still not always, so it's nice to know that it's worth the extra effort!
Fascinating as always. Thank you. A question however. In the first illustration, glass lenses are shown. Wouldn't plain glass windows have let in the same amount of heat or energy in such a setup?
Thank you! Huh, interesting question. I think I see what you mean. Perhaps by focusing on a point in the centre of the vessels it resulted in less heat loss from them? I imagine that by concentrating the rays that might also result in more conversion of the light into heat? I may need to ask a physicist...
Incidentally, de Caus's third variant was to have a frame of convex lenses to all be directed at the wall of the copper vessels rather than to be fixed within the vessel.
My thinking is this: The vessel is warmed by the sun shining of the surfaces exposed to the sun. Windows in the vessel could speed up the warming but ultimately the total energy received is limited by the area of the exposed surfaces. A lens can only collect and focus as much energy as its surface area allows. To be able to collect more energy Caus's third variant seems to collect and focus energy from multiple lenses and if these lenses have a greater surface area than the vessel, then that arrangement will achieve increased warming.
We do know that, but he might have been unsure about ?
Alternatively, it might not actually have been lenses, just the easiest (and strongest) shape at the time to make glass windows ?
Alternatively, he just had glass lenses, possibly low quality / scratched ones lying around, and he re-used them ?
De Caus certainly used lenses, as he specifically calls them "burning mirrors" in the text accompanying his illustration. I think the best explanation is that he simply didn't understand the problem - he did not have the same, or really any, concept of energy like we do today. His third variant would have solved the problem, however: having a frame of convex lenses all directed at the wall of the copper vessels rather than in the vessel wall.
Great reading!
Only small technical remarks - most of described machines work by shrinking and expansion of gas (air), not by condensation. Even Savery's machine works by mixed shrinking of air and condensation.
And Huygens is Christiaan, not Constantijn.
Thank you Hugo!
Yes, I sometimes clarify that it's the shrinkage of air, though after the initial sucking phase e.g. in Philo's machine it seems plausible to me that there might also be some water vapour condensing there too. In general, in the parlance of the time they often frame it as a matter of "dense vs rare", and although condensation now has a very specific meaning for the actual state change, at the time they tended not to talk of steam separately, but considered it a form of air.
I did say it was Constantijn's son. But as you're now the second person to misread this, it's very clear to me that I ought to edit the phrasing to make this clearer! Which I shall do now...
Today original thinkers can be reached by the veneer of advanced education.
The concept of perpetual motive can be closely approached using air pressure provided by a VAWT.
The air over hydraulic configuration can drive any machine with incredible force.
Combining this method with a hydraulic hub and one has motive power.
MORE to the story.....
Why haven't you mentioned the Worcester's water-commanding engine?
1663 description of "fire-water work" in Worcester's Century of Inventions:
“ An admirable and most forcible way to drive up water by fire; not by drawing or sucking it upwards, for that must be as the philosopher colleth it intra sphaeram activitatis, which is but at such a distance. But this way hath no bounder, if the vessel be strong enough ; for I have taken a piece of a whole cannon, whereof the end was burst, and filled it three quarters full of water, stopping and screwing up the broken end, as also the touchhole, and making a constant fire under it; within twenty-four hours it burst, and made a great crack : so that, having a way to make my vessels, so that they are strengthened by the force within them, and the one to fill after the other, I have seen the water run like a constant fountain-stream, forty feet high : one vessel of water, rarefied by fire, driveth up forty of cold water, and a man that tends the work, is but to turn two cocks, that one vessel of water being consumed, another begins to force and refill with cold water, and so successively, the fire being tended and kept constant, which the self-same person may likewise abundantly perform in the interim between the necessity ot turning the said cocks.”
Getting there! We’re up to the 1610s so far, but Part III will get to the mid-17thC. I alluded to Worcester’s machine briefly in my previous update post on perpetual motion, as being part of my investigation. It’s pretty murky though still, and I’m collecting some corroborating evidence. From that famous description you’ve quoted, it sounds like it used the expansive force of steam. But there are a few hints elsewhere about it.
That one I did mention in part I. I actually have a whole post about it from about a year ago, pointing out that it only used expansive force.
yes it seems it was only pushing