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Has anyone here researched Hero/Heron of Alexandria? I'm particularly interested in evidence regarding his active dates and inventions directly attributed to him. Most sources I've found place him around 60-70AD based on his mention of an eclipse that occurred in 62AD. That seems to be the generally accepted version and I haven't yet seen anything serious to contradict it. I'm also interested in separating those things amongst his writings where he was restating or editing the works of others, and instances of innovation on his part. There seems to be a recurrent theme that few, if any, of his major technological advances were recognized or properly exploited. Was this due to intellectual bias against practical work (ars vs techne)? Was it a result of the abundance of labor? Lack of supporting/complimentary technologies? Economic incentives? Your thoughts and/or direction to relavent sources are appreciated.
This issue was discussed long ago in this forum. Try doing a search.

I believe there is a bias. The bias is to look from our vantage point and to think that the invention of newton's dynamics and the steam engine as obvious and straight-forward. The best way to contextualize Heron's toy is to FIRST study the history of the steam engine and grasp how difficult it was to get to that point; i.e. study some science, technology and history of both (not dates, birthdays or ideosyncrasies of men, but how empirical observations led to concepts, to wrong turns, to laws). Then when you look back at Heron's toy you can truely and profoundly see how big the GAP was, how much had to be done and understood to get from a cute but powerless toy to a machine worthy of that name, i.e. one that harnesses enough thermal energy and converts it to coherent motion as to be even thought of as a possible substitute for animals (including human ones).

The bias arises because non-scientifically educated people think that only ideas shape our world. Although it is true (humans have a knack for castrating themselves), it is more important to know that nature and the laws of physics shape our world even more. Some ideas simply do not work. So please downsize the "theory" that ancients, and romans in particular, had a bias towards practical things.
Thanks for the reply Jeffrey,
I did look back at some of the older posts here, and I've also done some reading in various related texts (White, Landels, et al). All seem to agree on 60-70Ad as a suitable timeframe for Heron's works. Aside from learning about his work and technology in general, settling on the most reasonable date is one of my primary objctives.
I had initially assumed that the dioptra was one of his inventions, but it appears his was only describing it's use, since it was mentioned nearly a century earlier by Vitruvius. That answers my second line of inquiry. Although he discussed important concepts and sustantial matters, none of his own contrivances really had any practical application. I must therefore ammend my assessment of him as the Thomas Edison of his age. Perhaps I should compare him more with Leonardo Da Vinci. Interestingly, all the major components of the reciprocating steam engine are present in his works, but there were too many connections still to be made.
I was drawn to his works primarily by the surviving portions of his manuscript on the cheiroballistra or literally, the hand ballista. Aitor Iriarte has demonstrated that a workable but arguably underpowered machine can be built following the existing text. Eric Marsden, in his difinitive "Greek and Roman Artillery" found it difficult to imagine that Heron would have written about a weapon that ammounted to more of a toy than a serious piece of military ordinance. In an attempt ot correct this error he nearly doubled the diameter of the bronze washers which determine the dimensions of the rest of the machine. That change necessitated a host of other ammendments which were not present in the original. What I've learned is that if Heron's machine were anything other than a toy or novelty, it would be the exception rather than the rule. Thus, his changes to the original text are based on a faulty, or at least highly questionable premise.
Cheiroballistra may have been invented by him, but obviously gained wide practical traction in the Roman army so -- doubling the size of the washers might not've reproduced what he particularly described, but it would reproduce how such machines would've worked once amplified and put into practical use by the military engineers.
Quote:Cheiroballistra may have been invented by him, but obviously gained wide practical traction in the Roman army ....

Well, we know from Trajan's Column and the artifacts that a larger machine, carroballista?, was indeed fielded. I appears to have entirely replaced euthyone wood-framed scorpions from at least 100 AD forward. ( I think probably did so by the mid 80s, but that's another issue) :wink: There is no evidence that the "hand ballista" he described was ever adopted.

Quote:...doubling the size of the washers might not've reproduced what he particularly described, but it would reproduce how such machines would've worked once amplified and put into practical use by the military engineers.

Doubling the size of a rifle does not necessarily produce a workable cannon, just a very clumsy rifle. That is why cannons have things like elevating mechanisms, carriages, recoil mechanisms, and wheels. It's also why they don't need shoulder stocks, forehands, slings, and bayonet lugs. It's also why you rarely see a bolt-action howitzer. Once beyond human scale such a thing would be impractical. Many of Marsden's (and thus nearly everyone else's) interpretations of the texts were based on certain assumptions. In this instance I chose to examine a cornerstone of his argument, that Heron would not have written about a small and seemingly impractical weapon. What I've been discovering is that other than the instances where he is restating/editing the work of others, there are few if any practical applications of his designs. Without this rationale there is no excuse to improve upon the text by "adjusting" the numbers, adding components you think should be there, or ignoring ones that are.