Orsova ballista field trials to start.

[P. Clodius Secundus]

... envisaging the horsemen dismounting and wheeling out a carroballista surely isn't in keeping with the general context of cavalry manoeuvres!

You may have some difficulty explaining that to the Hussar Artillery. On this side of the pond I would refer you to "The Gallant Pelham" J.E.B. Stuart's boy wonder of the horse artillery. (one of his favorite toys was the 12lb Napoleon, designed by Verchere DeReffye BTW). As interesting an image as this conjures up, it is hampered by the lack of evidence that carroballista carts were ever ridden. I suppose they could have led the team from horseback and sidled up behind the cart to fire the weapon, but that's really stretching it.

....and I concluded that it must be a miniature catapult of some kind; a Hadrianic date suggests either the cheiroballistra itself, or the much less-well-known arcuballista, which I proposed might have been more like a standard crossbow.)....

It only suggests a cheiroballistra if you assume that Heron's design was actually adopted. It may well have been, but I've seen no objective proof. In it's absence I would fall back on the well-documented Xanten or better yet, the arcuballista which was presumably simpler to use while mounted.

[D B Campbell]

As interesting an image as this conjures up, it is hampered by the lack of evidence that carroballista carts were ever ridden. I suppose they could have led the team from horseback and sidled up behind the cart to fire the weapon, but that's really stretching it.

Gallant Pelham sounds fascinating. As does your idea for Roman horse artillery. Perhaps one of our historical novelist RATers will take up the challenge.

[Paullus Scipio]

Dan Howard wrote:

German reiters used various tactics, such as the caracole, that involved a single shot from a pistol before charging into combat. The pistol was discarded after that shot - no reloading involved. I don't see much difference between shooting a crossbow once from horseback and a legionaire throwing a pilum before charging the enemy. The point is to break up the formation before engaging.

I think there may be some confusion here – the ‘caracole’ (Spanish for snail) was a tactic which involved a column of horsemen riding up by ranks and discharging their pistols, then retiring to the rear to reload. It was described in manuals but was a disastrous failure whenever tried, for obvious reasons. The charge ‘sword in hand’ advocated by Gustavus Adolphus and others was far more successful. From a military viewpoint, I certainly don’t believe every Roman trooper was equipped with a very expensive and complex ‘cheiroballistra’, which was discarded after a single shot, when he had a quiver of seven javelins ( according to Josephus) which would do the job far better, much more cheaply…. hock: hock:

Randi wrote:

Mid 60s AD The Heron of Alexandria, the Edison of his day, writes the cheiroballistra text describing a hand-held belly-cocked weapon featuring a new type of iron frame. As Aitor’s work demonstrates, his treatise produces a workable machine, but it may have been underpowered or not considered a significant enough improvement to warrant replacing the Xanten type weapons.

…or alternately, as I suggested in my earlier post, Heron may well be misdated, since the dating is based on two assumptions – the similarity of the metal spring covers and frame to those on Trajan’s column, and the assumption that because he referred to a particular eclipse, he actually witnessed it. Neither of those assumptions is very convincing – if the metal frames became standard, he could have been writing much later, and given the Library of Alexandria, he certainly didn’t need to have witnessed the eclipse he theorised about…..

A hand-held Xanten type weapon is shown on Vedinnius’s tomb.

...I don't think that the absence of a base on the tombstone necessarily suggests 'hand-held'....the artist could have ommited a base for other reasons, such as lack of space - after all, what is there conveys the meaning clearly enough...


D. Campbell wrote:

It's fairly clear that the horsemen are shooting from horseback -- critics may carp that Arrian is not explicit on this point but, as you yourself will appreciate, envisaging the horsemen dismounting and wheeling out a carroballista surely isn't in keeping with the general context of cavalry manoeuvres! ……….

….As does your idea for Roman horse artillery. Perhaps one of our historical novelist RATers will take up the challenge.

There is nothing to suggest they are mounted at all, indeed they are also described slinging stones (difficult if not impossible from horseback – there never were any ‘mounted slingers’) and throwing stones by hand, to demolish a target – hence lots of fist-sized stones. Besides which, Arrian himself describes artillery operating with cavalry in his ‘Order of battle against the Alans’......so fact rather than historical fiction.

[D B Campbell]

There is nothing to suggest they are mounted at all,

Except that they are cavalry!

Besides which, Arrian himself describes artillery operating with cavalry in his ‘Order of battle against the Alans’.

But not by cavalry.

[P. Clodius Secundus]

Randi wrote:

A hand-held Xanten type weapon is shown on Vedinnius’s tomb.

...I don't think that the absence of a base on the tombstone necessarily suggests 'hand-held'....the artist could have ommited a base for other reasons, such as lack of space - after all, what is there conveys the meaning clearly enough...

Even if it's only 51/49 the win should go to "no base" by default.
Aside from that, why does everyone here immediately blame or make excuses for "the artist"? I for one am rather grateful they applied their meager skills for the benefit of posterity. Call me stubborn, but when faced "Sophie's Choice" between a pet theory and the work of an ancient artist I refuse to throw the artist under the bus in the name of expediency. I go back to the drawing board and look for a way that all the pieces might fit. If I get to defy convention and dogma in the process that just makes it all the more fun. :lol:
Just so you don't think I'm basing my judgement entirely on the absence of the base, here are a few other points to consider;

Aspect ratio of the frame..
Comparing the known remains of large euthyones (Ampurias, Caminreal, Cremona) all are undersprung compared to the Vitruvian "ideal". This would be easily accomodated in a stand mounted weapon where longer arms and correspondingly longer case will not significantly affect the handling. In a hand-held weapons it would make more sense to overspring and therefore shorten the draw. Like the Xanten find, the Vedennius frame appears tall/narrow/oversprung. Still with me? :wink:

Shape of the aperture...
Camireal and Cremona, both large scale, have an opening in the center stanchion that is shaped like a palladian window. Xanten and Vedennius share a single narrow arch. I have my own ideas why this might be so, but that's for another time.

Length of the arms...
From the carving it appears the bowstring is wrapped around the arms approximately 1/4 of the way up from the distal ends. This runs contrary to all other evidence. I can think of two rational explanations for this. One, the arms are drawn fully to the rear and what look like the tips of the arms are actually the tapered ends of a transverse belly rest. Or, unlike the gatraphetes where the handles were on the crescent, these have been moved to the ends of the arms where the shooter can add the pull of his arms to the weight of the draw.

Any of those help sway you?

[Crispvs]

Randi,

Why do you place so much faith in the proportions shown on the sculpture? Roman tombstones are notorious for their lack of attention to correct proportions. It may be true that some are accurate in their attention to proportionality, but many more seem to pay very little heed to actual physical proportions, unless of course you believe that people in those days had ears like trumpets, waists the same width as their shoulders and hands big enough to act like baseball 'mitts', to name just three out of a number of common proportional problems. As far as we know the Roman army did not contain any chimpanzees in the ranks, but looking at a good deal of funerary sculpture a naive person could be forgiven for thinking they did. :wink:

Given that sculptors were not always concerned to be faithful in their depiction of people, what is there which suggests that they would be faithful to the degree you imply in their depiction of a machine? Realistically the proportions of the scorpio shown on Moderatus' stele tell us nothing more than that we are looking at a depiction of a bolt shooter. We have absolutely no way of knowing whether or not its proportions bear any relationship at all to a real machine.

For a slightly longer discussion of these problems have a look at my article on provincial sculpture at the link below my signature.

Crispvs

[P. Clodius Secundus]

Crispus,
Like Duncan says, you pay your money and ride your ride. I put a degree of faith in sculptural evidence as a starting point because it is at least what a trained craftsman thought one looked like 2000 years ago. Because it is a "first edition" so to speak I can be reasonably sure that, aside from the effects of weathering, it hasn't been significantly altered or interpreted to fit someone else's agenda. Compare that to textural evidence which has been subjected to generations of copyists and translators. Even artifacts are not beyond "constructive ammendments" to fit assumptions.

[Paullus Scipio]

There is nothing to suggest they are mounted at all,

Except that they are cavalry!

Besides which, Arrian himself describes artillery operating with cavalry in his ‘Order of battle against the Alans’.

But not by cavalry.

I'll spell it out. There is nothing in the passage which suggests the men were mounted while carrying out this exercise, and as we have seen,(the full quote in my earlier post) the passage, having fully described the mounted exercises, complete with a conclusion then says : "In addition to this( the mounted exercises) shooting exercises of various kinds are performed."
Of the three referred to, two - slinging and hand-stones - must have been performed dismounted, and since a mounted man could not reload a 'machine' of any type, it follows that this too was done dismounted. Logically, what is being described are plainly dismounted exercises.

The Romans did not, so far as we know, have a corps of 'artilleryman' in Arrian's day. Arrian has told us that Cavalry can operate 'machines'/boltshooters of some kind. He also tells us that boltshooters were deployed on the flanks of the cavalry, at the very tips of a crescent formation ( which would be a very risky place for a detachment of lonely legionaries in the face of Sarmatian light cavalry, especially if the cavalry being supported moved! )

On balance of probability, I would suggest they were operated by cavalrymen, and probably of the carroballista type if they were to stay with cavalry.

As I have indicated, to me it seems too early for 'hand-held' artillery 'cheiroballistra' or 'manuballista' despite the shaky evidence of the assumed dating for Heron, and the tombstone. Furthermore, there is absolutely no evidence at all of any type that at this period, 'hand-held' machines were used on horseback. In fact I doubt if it is even physically possible. How would you carry it while riding for a start ? A moment's thought should convince anyone of the impossibility of such use.

Randi wrote:

Any of those help sway you?

...they would be very persuasive indeed, but I have the same difficulty as Crispus, namely that I find it difficult to believe a tombstone mason took the trouble to go find a real machine, measure it, and then produce a 'scale drawing', or even approximate one, on the tombstone and therefore it may be that too much is being read into the carving - which is more likely to simply recreate the general appearance of such a machine. As you yourself point out ("...contrary to all other evidence.."), the sculptor seems to have made at least one 'boo-boo' or careless mistake...
note: I did say 'not necessarily a machine without a base - I didn't rule out the possibility, merely pointed out it may be something else'...

Having said the above, Roman masons could, on occasion, reproduce something faithfully that was in front of them. It is noticeable that on 'trophy' monuments such as the base of Trajan's column, the weapon trophies are sculpted approximately 'life-sized' and with meticulous detail, being generally very accurate as far as we can tell.....but note the word 'approximately'.

[MeinPanzer]

Furthermore, there is absolutely no evidence at all of any type that at this period, 'hand-held' machines were used on horseback. In fact I doubt if it is even physically possible. How would you carry it while riding for a start ? A moment's thought should convince anyone of the impossibility of such use.

Slung over the back? There is abundant evidence for the use of cavalry crossbowmen among the ancient Chinese, and Chinese crossbows could get quite large and seem to have been quite cumbersome to reload, so it's not like this sort of thing is impossible.

[Paullus Scipio]

Furthermore, there is absolutely no evidence at all of any type that at this period, 'hand-held' machines were used on horseback. In fact I doubt if it is even physically possible. How would you carry it while riding for a start ? A moment's thought should convince anyone of the impossibility of such use.

Slung over the back? There is abundant evidence for the use of cavalry crossbowmen among the ancient Chinese, and Chinese crossbows could get quite large and seem to have been quite cumbersome to reload, so it's not like this sort of thing is impossible.

...The cheiroballistra as described by Heron is much larger and way heavier than even a 'wall-crossbow' - one only has to look at reconstructions such as the 'hand-held' cheiroballistra held by Bernard Jacobs on pp124-125 of Graham Sumner's "Roman Army -Wars of the Empire". The springs and arms are at right angles ( unlike a crossbow where everything is in the same plane) and I do not believe it would be practical to sling it over the back - just too heavy and cumbersome. I was wondering if someone would mention chinese mounted crossbowmen. While chinese crossbows, and European ones too, could get quite large, the larger types were not used by mounted crossbowmen. There are also mediaeval mounted crossbowmen, but these are not cavalry - they ride to and from battle but use their crossbows on foot.

In any event, it is debateable whether the 'cheiroballistra' was a hand-held machine - Marsden, Wilkins and others believe not. Heron's text is incomplete, so a base and winch parts could have been included. Further, as Wilkins points out, the purpose of a torsion machine with its complex parts is to obtain more power than a compound bow can deliver, and the 'cheiroballistra' has a draw-pull ( in Wilkins reconstruction) of over 335 kg - impossible for a 'belly-cocker'! The cheiroballistra also has a 25% increase in the size of the cross-section of the case of a Vitruvian 'Scorpio', implying a more powerful, heavier type - and the 'scorpio' was certainly stand mounted. This is consistent to with the stand mounted machines on Trajan's column. Who would build a complex torsion machine, and 'de-tune' it to human force levels, when a simpler compound bow like the 'gastraphetes' would do the job? Occam's razor surely applies.....

[samuli seppanen]

Thanks for the lengthy response, Crispvs! One correction to my earlier post: Iriarte made a convincing point for the "manuballista" in his 2000 article, not in 2003 as I stated.

First I'd like to say that I'm in no position to question Wilkins' expertise in the Greek and Latin artillery texts. My Latin is poor at best and I don't know any Greek. I'm sure Wilkins is a _very_ nice guy and knows a great deal about ancient artillery. I would very much like to get my hands on his JRMES articles to see what he has to say about the cheiroballistra. As some of you guys clearly know Wilkins personally, it's no surprise heated discussions start at the very moment when somebody mentions an inswinger or a gastraphes-style manuballista (like I did).

However, I think it's clear that the texts can be analyzed over and over again without ever reaching a consensus. All scholars so far (e.g. Marsden, Wilkins, Iriarte) have interpreted the same texts very differently, which means that it's very easy to fit the texts to fit one's preconceived ideas. For example, Marsden had the idea that cheiroballistra had to follow the old calibration formula, so he heightened and widened the cord bundles of the cheiroballistra by introducing "textual corruptions" into strategic places and interpreting the rest of the text so that it made sense (see Iriarte 2000). Marsden also added a winch, a base and a number of other modifications not present in the original text, similarly to Wilkins. As an archaeologist I'll work with the source material most familiar to me - archaeological evidence.

Much of Aitor's argument rests on the assumed positions of the missing stanchions of the Hatra frame. He seems to assume that these must have been in particular positions and that these positions preclude the effective use of the outswinging configuration.

However, Wilkins (2003) shows that other arrangements of the stanchions are possible and that it would indeed have been possible for the Hatra catapult to have been of outswinger configuration. When I asked him about the cuspings on the internal sides of the frame, he pointed out that longer arms would allow more leverage on the bowstring to produce more power. Such longer arms would need larger 'heels' to give stability to the arms themselves and the cuspings would therefore be ideally positioned to allow the arms to be drawn further back without the heels being obscured by the frame, with the heels moving into the cuspings as the arms were drawn back.

I could not agree more with Aitor - and Baatz for that matter (see his Hatra reconstruction). What does Wilkins mean by "larger heels stabilizing the arms"? Why not just make the heels thicker and heavier rather than longer? From a pure performance point of view the heels should be as short and light as possible. However, I don't know what problems doing that would cause. Anyways, large heels rob energy away from the bolt as they need to accelerate, too.

Have you read the Hatra ballista part in Baatz's 1975 article? If not and you're willing to spend some money on it, is available here:

[url:2r8f8l6u]http://www.jstor.org/pss/525936[/url]

Anyways, as shown in Baatz's article the Hatra ballista contained 8 close ended bronze corner fittings. Half of these were "mirrored" but otherwise the same as the other half. The fact that these corner fittings were close-ended means that they could only have been attached to the end of a beam (e.g. a side stanchion). The drawings in Baatz's article clearly show that each corner of the Hatra ballista frame had one of these fittings. Wilkins himself (2000: 68) provides us with a few excavation/conservation photos which too make this clear. So, in a nutshell, there were two vertical side stanchions at each end of the Hatra ballista frame and the bronze corner fittings were attached to their ends. It is very difficult to explain the corner fittings in any other way. This is what effectively forces the Hatra ballista to be an inswinger rather than outswinger. To circumvent this problem (if he was indeed aware of it) Wilkins (2000: 68) moved the inner side stanchion towards the middle of the frame. This allowed him to force the Hatra ballista to fit his outswinger theory at the cost of ignoring the inner corner fittings which have been attached to vertical beams. And if the beams don't go from bottom to the top, they serve absolutely no purpose.

Unfortunately the Hatra ballista is not the only problem for Wilkins' outswinger theory - and it's just that, a theory - poorly backed up by archaeological evidence. Iriarte (2000: 63, 66) tested how the existing kambestria (field-frame) finds would have worked in the outswinger configuration. The results were mixed, with maximum arm travel between 38 and 68 degrees. In an inswinger configuration with same kambestria the arm travel was between 66 and 125 degrees - roughly double that in the inswinger configuration. Although Iriarte (2000) initially reconstructed his cheiroballistra as an outswinger, it seems he had a hard time convincing even himself of that setup. Later in 2003 he "changed camps" in his "The Inswinger Theory" article to which I linked earlier.

At this point I should say that Alan Wilkins has been criticised more than once here on RAT for adding parts to his reconstructions which have not been found in the archaeological record. However, none of the surviving frames constitute the complete head units of the catapults they came from and it is debatable whether any of the surviving frames retain even all of their original metallic parts. Simply joining up the surviving parts and assuming that they constitute the entire frame ignores the fact that significant potions may be missing. After all, have any ratchets or other windlass gear been found in association with any of the known frames? We can be fairly sure that winches would have contained or been associated with at least some metal parts, as would the trigger. If these essential items are missing, why assume that what we actually have is complete? It is obvious that although the surviving treatises contain much minutiae on certain parts of their respective machines, other parts are less carefully described and some parts may well not have been mentioned. How often are the bars which rest atop the washers mentioned? Yet without these essential pieces the whole machine would be useless. We are lucky to have the evidence for them from the archaeological record, what what if we didn't? Also, how do we know that we are arranging the surviving elements of the frames the correct way up? Aitor on more than one occasion has stated that inswinger configurations are obvious from the positions of the side stanchions on the surviving spring frames but those same spring frames need simply to be placed the opposite way up to make an outswinging configuration equally obvious.

There are several potential explanations for our apparent lack of other ballista parts (e.g. winches, ratchets). A thorough study of the existing excavation reports and finds is definitely required: excavators and (find) cataloguers are usually generalists rather than (artillery) specialists. In addition, they simply don't have time to do extensive background research on every object found from the excavation. Due to this "difficult to identify" objects (e.g. ballista parts) are often labeled with a generic term or completely misinterpreted. Also, if the find context is not immediately obvious parts belonging to the same machine this relation can easily get lost in the final archaeological data.

If indeed no other ballista parts have been excavated, there are several explanations. The most likely is that the current finds do represent the situation when the finds were deposited - sans organic material material which has already detoriated. This would mean that the ballistas were not in operating order to begin with. Archaeological data contains almost exclusively finds which have little or no value - mostly broken and discarded items, trash, etc. Expensive items are very rare except in some special find contexts (e.g. tombs). Anything valuable and/or useful - such as an entire ballista - was taken good care of and did not often end up into the archaeological context. The Hatra ballista seems to be an exception, apparently because it was covered by rocks which made scavenging more trouble than it was worth. However, without studying the excavation reports and finds all of this is difficult to prove one way or another.

Anyway, Wilkins tried to solve the the lack of archaeological proof for his outswinger theory by introducing the famous bronze locking plates. I have to say that when I first saw the lock plates I got the impression that Wilkins was a mere hobbyist inventing parts as needed. Later, when I learned that Wilkins was actually a scholar, I was rather surprised. As you say, lack of bronze locking plates in archaeological evidence does not prove they could not have existed. However, none have been found and they're entirely unnecessary for an inswinger. Also, if the ancient engineers had wanted to create iron kambestria suitable for an outswinger configuration, they could have created a simpler, lighter and cheaper system.

Wilkins has also pointed out that the inswinger configuration also suffers from the flaw that as the ends of the arms draw close to each other before progressing forwards, much of the tension the bowstring has initially picked up is lost as the string goes momentarily slack, meaning that the net gain in power from the arms increased arc of travel is significantly less than it might otherwise be.

I did some measuring on my own inswinger CAD model. The string moves ~4,7cm forward during first fourth of the arm movement (~25 degrees) and additional ~5,3cm during second fourth. During third fourth the string moves forward only ~2,0cm. I assume this phase is what Wilkins means when he talks about "slackening of the string". However, during the last fourth the string moves an astounding 15cm forward. As the arms themselves have accelerated for the whole duration of the shot, this last fourth takes a lot less time than the first fourth, increasing the bolt velocity even further. So this final phase of arm movement is critical for the velocity of the bolt. However, this rapid acceleration of the string (and bolt) comes at the cost of reducing the leverage of the arms. This means the bolts have to be light to benefit. I think the benefits of this last phase of arm movement are clearly visible in high velocities produced by Nick's reconstruction.

Regarding Wilkins' note about the "slackening of the string"... it should be noted that the bolt and string still retain their forward movement regardless of what arms are doing. So I don't think the string ever goes "slack" - rather it's acceleration decreases (or stops?) momentarily. Also, the last phase of arm movement more than makes up for this slack phase. I think the best way to see what's really going on would be to record a few shots using a high-speed camera.

Samuli

EDIT: Most have probably already lost sight of Nick's blog about his Orsova reconstruction: http://wattsunique.com/blog/
EDIT: fixed a typo (inswinger -> outswinger)

[Gaius Julius Caesar]

That is pretty impressive, the teething problems aside.
An infantrymans nightmare.
I think there would be a lot of expertise put into forging these pieces.
Roman metal working was pretty darned good. I look forward to seeing more.

Nice location for such things btw!

[D B Campbell]

Paulus makes a number of unwarranted assumptions in his post.

... two - slinging and hand-stones - must have been performed dismounted ...

Must, in your opinion, have been performed dismounted.

... and since a mounted man could not reload a 'machine' of any type ...

Again, a cavalryman could not, in your opinion, reload a machine of any type.

... boltshooters were deployed on the flanks of the cavalry, at the very tips of a crescent formation ( which would be a very risky place for a detachment of lonely legionaries in the face of Sarmatian light cavalry, especially if the cavalry being supported moved! )

Again, this is only a risky position in your opinion.

I notice you persist in emphasizing that Arrian's catapults were deployed "on the flanks of the cavalry", when Arrian says no such thing. In fact, as expected, they are deployed amongst other missile troops; archers on one flank and javelinmen on the other. You have manufactured a completely spurious link with cavalry here.

there is absolutely no evidence at all of any type that at this period, 'hand-held' machines were used on horseback. In fact I doubt if it is even physically possible.

Others have demonstrated that you are mistaken in this belief.

The cheiroballistra as described by Heron is much larger and way heavier than even a 'wall-crossbow' - one only has to look at reconstructions such as the 'hand-held' cheiroballistra held by Bernard Jacobs on pp124-125 of Graham Sumner's "Roman Army -Wars of the Empire".

I cannot comment on Bernard Jacobs' version, as I've never seen it. But I would have thought the logical course would have been to look at Heron's Cheiroballistra itself, rather than someone else's interpretation of it.

In any event, it is debateable whether the 'cheiroballistra' was a hand-held machine - Marsden, Wilkins and others believe not.

It is unfair to impugn Marsden here. In the 1960s, nobody imagined that the ancients had hand-held mechanical weapons. Alan Wilkins has taken it upon himself to continue Marsden's work, and has done a sterling job. I wonder who your "others" are?

Heron's text is incomplete, so a base and winch parts could have been included. Further, as Wilkins points out, the purpose of a torsion machine with its complex parts is to obtain more power than a compound bow can deliver, and the 'cheiroballistra' has a draw-pull ( in Wilkins reconstruction) of over 335 kg - impossible for a 'belly-cocker'! The cheiroballistra also has a 25% increase in the size of the cross-section of the case of a Vitruvian 'Scorpio', implying a more powerful, heavier type - and the 'scorpio' was certainly stand mounted.

You are clearly unaware of the wider debate on the Cheiroballistra, as you are simply describing the Marsden/Wilkins version. You should perhaps have a look at some other threads before digging yourself any deeper into the mire.

[P. Clodius Secundus]

..
...Wilkins points out, the purpose of a torsion machine with its complex parts is to obtain more power than a compound bow can deliver, and the 'cheiroballistra' has a draw-pull ( in Wilkins reconstruction) of over 335 kg - impossible for a 'belly-cocker'! The cheiroballistra also has a 25% increase in the size of the cross-section of the case of a Vitruvian 'Scorpio', implying a more powerful, heavier type - and the 'scorpio' was certainly stand mounted. This is consistent to with the stand mounted machines on Trajan's column. Who would build a complex torsion machine, and 'de-tune' it to human force levels, when a simpler compound bow like the 'gastraphetes' would do the job? Occam's razor surely applies.....

The only reason Wilkins' machine has a draw that heavy is because he and Marsden disagreed with the manuscripts and nearly doubled the given dimension for the washers. The with the washers as written the result would be little more than a toy. Well, if Heron of Alexandria had been better at scaling up his "toys" into practical machines we might have been using steam turbines for the last two thousand years. :wink:
What makes you assume that the machines on Trajan's were de-tuned to make hand held weapon? I propose exactly the opposite. Heron designed a new weapon with an in-swinging layout that increased the range of arm travel and velocity. It may or may not have replaced the Xanten type as a hand held weapon. Someone figured out that if you scaled the weapon up and used a winch you could really take advantage of the increased power. Now as a winched, stand mounted, and crew-served weapon it no longer needed a belly rest or a sliding "slider" to cock the arms. (Wilkins includes the crescent on his reconstruction even though it serves no purpose and the only other weapon ever to use one was the hand-held belly-cocker gastraphetes.) The transition probably took place sometime before 87 AD which is why both the Romans and Dacians are seen using them on Trajan's Column. Because the case of stand mounted in-swinger is only about half the length of an out-swinger they could be used directly from a mule cart. This turned then into mobile field artillery. Light, highly mobile field pieces have been used in conjunction with cavalry on many occasions. Hussars with their "gallopers", Stuart's Horse Artillery, and the french 75mm are just a few more modern examples. I have trouble envisioning cavalry efficiently operating any torsion weapon from horseback. That doesn't mean it can't be done, bu using them as dismounted shock troops/dragoons make more sense. Wilder's Lightning Brigade of the ACW springs to mind as an example.

[Dan Howard]

Contrary to the propoganda, there were plenty of medieval knights who wielded crossbows from horseback - both for hunting and on the field. Maximillian himself is depicted with one. I have no idea whether these crossbows had much in common with ancient variants, but there is abundant evidence to show that some types of crossbow were shot and reloaded from horseback. China is another example that has already been mentioned.