Some Quotes of Mc Leod in discussing King Tut's bows;
p20, bow 14 "the facing strip at the grip has now sprung away from the core, thereby disclosing the structure..... The core is backed with a layer of gelatinous substance,..."
Bows 17, 18, 21,22, 23, 25, 26, 27, 29, " Backing of a gelatinous substance"
P26, bow 29 "Bad condition" does not say how except structure is visible.
p. 27, bows 30-32, " "'three neatly made composite bows, now, unfortunately in parlous condition, their gelatinous cores at some early period having become viscid, with the result that they leaked out, and dried in a solid black mass'"
p 31-32 "gelatinous substance...where one would normally expect sinew; possibly it is the end-product of the degeneration of sinew. It is known that if certain animal products are exposed to an excess of water for a lengthy period of time, a complete breakdown of structure will take place by the chemical action known as hydrolysis; the protiens are degraded, the organized structures disappear, and a form of gelatine results"
there is another paragraph.
He also does not discuss how the structure of many of these bows can be seen by a telegraphing of the glue lines of the laminates through the birch bark. The structure of most of the bows is at least guessed at.
You have probably noted this telegraphing yourself. (this is a woodworking term) Jack
Adam Karpowicz
Thanks Jack, this is very interesting. He seems to suggest the bows were exposed to water or at least very high humidity. It is surprising - I would think the conditions had to be very dry in the desert. I have a suspicion the glue had a chemical (a preservative?) added which could attract moisture, causing the degradation of the protein. (I am always very interested in such details as a former chemist who actually researched the glue.)
The "puffing-up" effect is, however, rather different. I think the individual fibers of sinew would contract with age, thus loosening the structure of the layers. Gradual contraction would be normal for the fibers and also for the glue as the humidity cycled in the graves. This could make an impression of puffing up as you say in the article when the fibers become separated and loosened. Very interesting.
Adam
jack farrell
Adam; My thinking is that birch glue figures into the Tut bow problem. There was probably just some slight humidity.
In the Miran case, salt is a recurring issue in Xinjaing burials. -j-
Andrew Hall
I had a chance to look at the Ancient Egyptian angular composite in the Pitt-Rivers museum last year (unfortunately under glass). This does not show any evidence of puffing-up of the sinew. Most of the bow is still covered by bark, but regions of damage allow the internal structure to be seen. It is rather difficult to determine what is sinew, as both sinew and horn seem to have merged into a seamless layer with no evidence of fibres. This layer is thick and white on the back, thin and white on the sides and thick and white over dark streaks on the belly. Presumably the solid white was sinew and the region with dark streaks horn (sinew wrapping over horn on belly). The layers appear to have similar brittleness (more brittle than the intact wooden core), as most of the breaks flow through both. The horn/sinew appear to be in their original positions (no sign of becoming viscid and leaking through the bark).
I wonder if Miran is very occasionally subject to flash floods from rainfall in the nearby mountains (less than 20 miles away). If you look at the town on GoogleEarth, it appears to be in a region of run-off deposits from the mountains. If part of the grave was "leakier" than the remainder for some reason, it might also explain the localised damage at one end of the bows.
I have seen an 18th C Turkish flight bow that has suffered water damage. This has "puffed-up" sinew that has pulled away from the core. (Sad that the bow is in that condition, but useful for seeing the internal structure).
Andrew
Adam Karpowicz
Thanks for the responses. It seems the degradation of the sinew layer may be manifested in both the effect of pulling away from the core and from loosening of the structure. I believe these effects are caused by the occasional very contact with either water or very high humidity, followed by drying.
The damage in the angulat bows is a puzzle still to be solved. I wonder if the glue has been analyzed yet.
Adam
Bede
Adam,
Humidity in the tombs of the Valley of the Kings has been remarked upon for many years. Despite the surface being very dry there is some movement of the water table. Recently the moisture in the breathing of tourists has contributed.
One of the problems with wall painting has been the deposition of salt crystals from water seeping through the stone.
The Tarim Basin in Central Asia has been renowned for the unpredictability of the water flows of its rivers, both on the surface and below it. Burials that were deeper had more effect from moisture and decomposition of bodies than shallow burials in sand.
jack farrell
As I remember, McLeod mentions that there are raw horns used on a funerary offering in the same tomb which did not suffer similar damage.
I believe that to write the book, Mc Leod did not examine the bows but operated from Carter's original notes and photographs not stored with the bows themselves. I do not think anyone has examined the bows in hand since Carter, the original archaeologist of the Tut tomb.
Bede
Here is what McLeod wrote in the Introduction:
DESCRIPTIONS are based primarily on the notes of Mace and Carter, though these have been edited, emended, and rearranged. 1 Further details have been added from Burton's photographs without comment. Descriptive data enclosed within square brackets have been added by B. Turzynski, from personal observation of the bows in Cairo. The decoration of each bow is described in zones, beginning at the grip and working towards the tips; each zone of decoration is likewise described from grip towards the tips.
