Yesterday we had a knapping session in the department lab. The above is an old Patterson’s Camp Coffee bottle base recovered from Chorlton Ees, and as can be seen, the glass is thick, uneven and with bubbles. Because of its square form I decided to try quartering it following the method described by Stanley Porteus (1931: 111-112) recorded after observing an aboriginal knapper producing blanks for Kimberley Points. The first step is to use a number eight wire to remove the base, and in this I was unsuccessful. The thickness of the base (~9mm) made it too strong, however during the process one of the side panels fractured nicely. I shifted to a small hard hammer and worked along the second longitudinal edge of of the fractured panel and I was able to remove it cleanly. Perhaps the subject of another post, but there were clear sonic signals as to how thick the glass was at each point, and I responded to that iteratively with the amount of ‘umf’ I applied.
This gave me confidence and I continued working along the remaining longitudinal edges. Voila, bottle quartered into four usable blanks using a small hammerstone.
I have tried this process before with a modern Bombay Sapphire bottle and it didn’t work. That I believe is because of the thickness of the glass being used. Like most modern glass bottles the Bombay Sapphire is well engineered presumably to optimise strength and minimise materials used, therefore weight. Consequently the Bombay Sapphire fractured unpredictably. The quality of the glass is everything here. Whilst the uneven thickness and bubbles on old glass present their own set of problems, the actual thickness provides some internal cohesion that makes it relatively forgiving to manipulation and modification. This suggests to me that Kimberley Points were ‘of their time’, in that the uneven thickness of early glass gave it qualities akin to a stone flake, and these were recognised as such by aboriginals. This similarity has diminished over time as glass has become more engineered. Aboriginals continued knapping materials such as Pyrex and window glass into the 1980s (Akerman pers. com.), and the methods would seem to have adapted as materials developed. Within this relatively short historical period a really interesting dialogue between human skilled practice and material development has played out. This was in tandem with an aboriginal recognition of the new qualities such as size, colour and transparency that could be marshalled into the traditional production process. In my own modest way I am, following in this tradition, and currently working on a ‘Glasgow’ Kimberley Point, which I am sure will be the subject of a post soon.
Porteus, S.D. 1931. The psychology of a primitive people. London. Butler and Tanner Ltd.