Studies in Organic Archaeometry III - Prehistoric adhesives: alternatives to birch bark pitch could be ruled out

The prehistoric adhesive used in central and northern Europe was most frequ ently prepared from the bark of the birch by means of a thermic process, us ually assumed to have been pyrolysis to yield (via the intermediate step of a tar) a pitch. In order to rule out that the ancient products might have been made either by a simple extraction or even more simply - by using a natural sap, such s tarting materials were studied. Although after drying up and heating both s howed reasonably good adhesive properties, the C-13-nmr spectra were remark ably different from those obtained from prehistoric agglutinants, e.g., giv ing no indication for the presence of betulin. Thus these two conceivable alternatives for the ancient preparation of the material in question can now be ruled out: the prehistoric adhesives can re ally be considered as pitch, prepared from the bark of the birch.