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Wednesday, 25 May 2016

Whatever happened to the great stone lift?

.......... so all those nice enthusiastic people at UCL decided not to lift a stone at all, but to pull it along on the lawn instead.......

Couldn't resist this pic when I saw it!


sciencebod said...

First instalment: I've been holding off doing my own crit' on the Gordon Square project, Brian, while I dredge up A-Level physics done well over half a century ago, knowing deep down in my guts that the approach taken was deeply misguided.

Thoughts crystallized over breakfast this morning, so I may do a posting later in the day, including some of my own photographs from Gordon Square of the initial efforts, which tell a very different story from the press releases and self-congratulatory headlines.(Admittedly I didn't stay right to the end, so missed the "spectacular" turns of speed).

Lifting and carrying or dragging? Yes, at first sight one might think it's easier the second way, letting terra firma (or not so firma in some places en route from A to B, whether 140 miles or 140 yards) support the weight and take most of the strain.

That's highly simplistic needless to say. If the block stays in contact with either the ground, or with impromptu log tracks, or even a sycamore sled on log tracks, one is having to overcome the force of friction as well as overcoming the initial inertia to get the block moving (while admittedly there's no lifting work against gravity).

But frictional forces can be considerable, and need some additional input of technology, or chemistry, to reduce. Keeping everything well lubricated with oil or even water may help, but there's really no substitute for having a series of closely-spaced metal rollers on individual axles, with ballbearings and lubricant as per airport security check-in. Friction then works in one's favour, giving sufficient grip that allows the rollers to rotate, and making it easy to get the block - or holiday suitcase - gliding along effortlessly.

But I say the imagined Neolithic means for reducing friction, while OK for a short demo in a London square, would not have have made longer tows a prcatical proposition, even with scores of fit blokes.

Let's look briefly at the alternative - lifting and manually transporting clear of the ground. Straightaway one has eliminated friction (except that needed between footwear and ground to maintain a firm foothold and forward propulsion). Yes, there's the initial lifting work against gravity, calculated as the product of mass x g x height, but that's shared out equally between everyone. Then there's the work needed to overcome inertia and get the mass moving (which as flagged up already applies when hauling anyway). But let's not forget the laws of motion: once the object is moving, then in the absenc of friction it will tend to STAY MOVING, inertia in a different guise, dynamic not static, and actually then needs work to bring it back to a halt, so the inertial work is a minor factor.

Continued on 2nd instalment

sciencebod said...

2nd instalment (4096 character limit per comment!)

The major factor when lifting AND carrying is biomechanics. The human body is not rigid, it has joints, the ones at the knees being crucial, tending to fold and crumple when attempting to carry too large a large weight. The greater the initial displacement from the vertical, the greater the mechanical advantage of the leverage at the joint tending to make it fold. The main input of work is that required to contract muscles in the thigh especially that keep the leg straight. Look at the thighs of a weight lifter! Those biomechanical forces are not readily calculated, but we are back to numbers: get a sufficient number of folk to share the weight out equally, and there's a corresponding linear reduction in the amount of muscular biomechanical work need to keep the legs straight. The biomechanical strain doubles briefly on each knee joint, obviously, when walking, i.e, transporting due to there being intermittently just one foot at a time on the ground, but again, the numbers and random strides making helps keep that to a reasonable minimum.

Overall, I reckon that the effort and work against gravity, inertia and biomechanics is likely to be no greater when lifting and carrying than hauling, and has the overriding advantage (surely) of there being no friction to worry about, and being better able to negotiate rough terrain by judicious twists and turns in the chosen trajectory.

BRIAN JOHN said...

If the Millennium Stone Pull was anything to go by, friction beneath the sledge was a huge problem. On farmland and common land pulling the stone became well nigh impossible, and the practicalities of using an endless stream of logs as rollers beneath the sledge runners soon got the better of the organizers. They decided to use asphalt roads instead, and even there friction was a huge problem -- so Netlon low-friction plastic netting was used, laid on the roads in sections about 40m long, if I remember rightly. The whole thing was of course a complete farce, and proved to all of us involved that moving one 2 tonne stone to Stonehenge, let alone 80, would have been beyond the capacity of even the smartest Neolithic warriors.

BRIAN JOHN said...

On the lifting scenario, the stone has to be lifted vertically, and that means supporting beams strong enough to take it -- with the weight of the beams significantly adding to the weight being carried. If you just have rope or netting slings under the stone, there is a sideways pressure on the carriers in addition to the downward pressure of the load -- which would make the task horribly uncomfortable, given that at least 20 people (that's just a guess) would be involved, all getting in each other's way in what would be in any case hostile terrain. Nah -- forget it.....

sciencebod said...

Link to English Heritage site, with photo of a bluestone with highly smoothed-off longitudinal groove:

The caption reads:

"One of the bluestones at Stonehenge, which shows clear signs of being shaped to fit together with other stones".

Compare with the caption to the same bluestone in Julian C. Richard's EH-commissioned tourist guide which shows a greater degree of open-mindedness:

"An elegantly grooved stone in the bluestone horseshoe, possibly intended to be jointed to a similar stone with a corresponding tongue".

Yup, I'm with you there JCR (not to be confused btw with York University's Julian N.Richards) and until such a time as a complementary tongued bluestone is found, or even a fragment thereof with remnnants of a tongue, then the T-in-G idea has to be seen as untested hypothesis, i.e. pseudoscience, and heaven knows there's enough of that as it is. I'd go further and take this opportunity to say shame on EH for its all-too-typical top-down premptive strike, one that tries to impose its own narrative, blocking out those of us attempting to seek new angles that attempt to RESOLVE mysteries instead of using them as a cash machine.

Someone went to a lot of trouble to make and smooth off that groove, and it should be the signal surely to recognize that there's an awful lot we still don't know about Stonehenge, as the banner credo of this site makes clear. Some might say we've scarcely started, thanks to all the set-in-stone "received wisdom" being dumped upon us (and scrupulous avoidance of the E word as regards the purpose of Stonehenge, or even the more euphemistic 'sky burial', despite the easy-to spot-Seahenge ground plan).

One possibility is that the groove was designed for transport, intending later to remove or somehow conceal from view. Might it have been a locating slot for a hardwood timber pole, to serve as yoke, the latter attached firmly by binding round with lots of rope or netting, the latter taking some of the strain off the yoke. Admittedly a single yoke would need some impossibly strong shoulders for transport, but it might have been a primary one, with lots more attached at right angles left and right, some at least well clear of the stone, such that space is created for 50 or more shoulders, their owners well spaced, not tripping over each others' feet.

There must clearly have been some innovative transport know-how that one can only guesss at, simply to explain the transport of the much bigger sarsens, albeit over much shorter distances. Dare on suggest that distance was considered no object, once you had the means to insert scores of carriers per monolith through 'enlarging' the effective size of the stone, admittedly some extra weight too, though modest, in a way that provided an extending framework of shoulder yokes?

Colin Berry

Jon Morris said...

"Someone went to a lot of trouble to make and smooth off that groove, and it should be the signal surely to recognize that there's an awful lot we still don't know about Stonehenge"

It's unusual that groove. If the archaeologists can some day determine what Stonehenge was built for, they may be able to single out oddities that do not fit the pattern. If the oddities are then looked at, they may show potential original intended purposes for the bluestones (but only if both purposes are heavily related): This might then show in what location to look for traces of that original monument (It is fairly certain that the bluestones came first in the sequence of events that led to the stone version of Stonehenge). Finding a monument's traces in a location predicted by purpose would put a fairly definitive end to doubt.

There would be a certain irony if the original layout and purpose of the bluestones had no resemblance to the thing that we call Stonehenge: All the current research is directed to looking for places which have features that fit the pre-conceived view.

BRIAN JOHN said...

Very true, Jon. It is normally assumes that Stonehenge was the pinnacle or the crowning glory of Late Neolithic / Early Bronze Age civilisation. But people have often argued in the past that it might have been a bit of a mish-mash, built from stones plundered from other monuments or just picked up in the landscape. Kellaway and others have argued that the bluestones were simply plundered from long barrows -- that's one explanation of why so many of them have been destroyed. (Who knows how many there were originally?) So instead of it being a temple to the dead, or a Neolithiv hospital filled with healing stones, maybe (as I have suggested more than once) it was just a folly or a fantasy, built by a family obsessed with mad ideas while the rest of the Wessex population looked on and shook their heads?

sciencebod said...

There's a possible handle on "purpose" with all those cremated bones, some 50,000 fragments we're told from at least 60 people, both sexes, excavated back in the 20s, and then stowed for safe keeping in one of the Aubrey holes/pits. What's the betting that if you picked an archaeologist at random from Yellow Pages, or should that be Yellowed Pages, and asked how those bones were generated they'd tell you that WHOLE bodies were cremated either on site (or at numerous remote take-away locations of Britain according to Mike P-P - according to a brief chat I had with him on Monday at Gordon Square - and thus 'brought in from outside').

But that's an assumption, and I'm willing to bet an untested one, namely that there was whole body cremation. I'll make a prediction: if there ever becomes a way of distinguishing between bones from a whole body cremation as distinct from bones from an excarnated skeleton, it will be the latter that will be shown by analysis. That then offers a rationale for those igneous bluestones. They were preferred as 'sky burial' bird perches initially being easy to keep clean (important when the low tops were at human eye level or lower). But once the technology had evolved that allowed for transport and raising of taller sarsen monoliths, with the lintels way above eye level, then there was no longer so pressing a need for non-porous stone. The bluestones then became largely surplus to requirements, but still functional, so were relocated to make first a makeshift cobbled-together circle then a horseshoe, each at a less conspicuous position INSIDE its respective sarsen counterparts, barely qualifying as megalithic, more funereal-looking headstone.

Jon Morris said...

"So instead of it being a temple to the dead, or a Neolithiv hospital filled with healing stones, maybe (as I have suggested more than once) it was just a folly or a fantasy, built by a family obsessed with mad ideas while the rest of the Wessex population looked on and shook their heads?"

Could be Brian. I'm going to go back to Stonehenge one day to take a look at that groove (probably when Neil gets over here). But you never know; the archaeos might find something, so it's probably best left until the Preseli venture is finished.