Stone Age Glue
When the Diggings team worked with Dr Gershon Edelstein at Ein Yael to uncover a Roman villa - possibly the country residence of the governor of Jerusalem - we had little idea of what would later become of the place. In fact, Edelstein has turned it into a "living history" museum where volunteers live as first century AD Jews, cooking, spinning, weaving, working with wood or stone and, of course, dressing, in ways that the archaeological evidence shows their ancestors did. The museum is a very popular attraction, with school trips by the dozen swarming over the place and poking their fingers into everything and asking the sort of questions children ask.
It may seem like a gimmick - and certainly we wonder where the Roman villa fits into all this - but such projects have a serious purpose. It is only as we try to face the problems of life with the techniques and resources available to people of the time that we can understand some of the solutions that they adopted - and sometimes we are surprised at just how sophisticated those solutions really were, even if they didn't have plastic and nano-technology.
Recently researchers in South Africa have been doing something of the same sort, but this time on tools from the Stone Age. This was the time when what passed for humans were bow-legged half-apes with overmuch facial hair and the pieces of flint that they used for spearheads were attached to the wooden hafts with a simple "glue" of acacia gum.
The odd thing was that the "glue" appeared to have been mixed with a reddish pigment rich in iron, but anthropologists had a ready solution. These people were clearly starting to develop human-like brains and they smeared the heads of their spears with red as a sort of imitative magic to "bring" the blood that they hoped would soon be staining them in earnest. Probably there was a shaman of sorts involved and we get the impression of shaggy men with animal skins round their waists queueing up to have an even wilder witchdoctor chant over their weapons and add a dash of red paint.
The researchers from the University of Witwatersrand wanted to recreate these tools and test the effectiveness of the "glue", so the necessary straight branches and broken flint were assembled and someone was sent out to gather the acacia gum.
Melting the stuff was easy and it proved satisfactorily simple to dip one end of a flint in the brew and then wedge it into the split end of the branch. The delighted scientists pranced around a bit with the finished product, admiring their Stone Age abilities, and then someone suggested that they jab something with the spear. The result was disastrous: the brittle gum shattered, the flint fell out and the discomfitted researcher was left to face a sabre-toothed tiger armed with a stick with a split end.
Even worse, refraining from using the spear was little better, as the gum hardened and lost its adhesive properties and after a few days in the African heat the flint simply fell out of its own accord!
The researchers tried everything: they heated the gum to make it hotter or cooler, they applied extra coatings of the stuff, they added bindings of leather thongs, but all to no avail. The gum was just totally unusuable - yet their Stone Age predecessors had used it and apparently very effectually, as the stone tools found during a decade of excavations at the Sibudu Cave showed.
It was then that someone, more out of desperation than anything else, suggested that they try mixing the gum with the red pigment. The result was encouraging, for the glue held the flint in place for days on end and when the spear was used, but when they tried it again, the glue failed - and kept on failing on the third and fourth attempts.
Eventually the researchers worked out what they were doing wrong. Making the glue required precise amounts of gum and pigment, it required precise temperatures which could only be maintained - using Stone Age techniques - by using particular types of wood, and it required precise humidity, which you got by keeping the pot at just the right distance from a fire made with just the right kind of green wood.
If the temperature was too hot, the glue contained air bubbles; if it was too dry it didn't stick; if it was too wet it was weak. The astonished scientists concluded, "The Sibudu Cave's Stone Age inhabitants were competent chemists, alchemists and pyrotechnologists."
Even more baffling, the glue-making method revealed a thoroughly modern intelligence. "The glue maker needs to pay careful attention to the condition of ingredients before and during the procedure and must be able to switch attention between aspects of the methodology, To hold many courses of action in the mind involves multitasking. This is one trait of modern human minds, notwithstanding that even today, some people find multi-level operations difficult."
It is amusing to compare - try Google Images - early pictures of Neanderthal Man with the results of research carried out by Dr Edward Rubin, director of Berkeley Laboratory's Genomic Division. The early pictures show beetle-browed individuals as hairy as chimpanzees shuffling along clutching branches as crude clubs. Dr Rubin's picture, based on his analysis of Neanderthal DNA, is of the girl next door or the chap sitting behind the desk in the manager's office.
Primitive man? Don't make me laugh.
© Kendall K. Down 2009
