Captain Flint by Dr Mc Neil

There is only one certainty about a career as a scientist – it is not for big-headed people. When you are trying to find a meaning in a jumble of apparently unrelated facts it is infinitely easier to go down a cul-de-sac than a motorway. Looking back from this vantage point in time I can see clearly that my dabblings may have created more non-scientific questions than answers, but many fewer scientific ones than I should have done if I had been any good at research.

So when the questions are asked “what did you do in the lab, doctor?” the answer must be “not a lot”. “Can you honestly compare yourself to Darwin?” - “No, but the outlines of the theory of evolution were the work of Erasmus, not Charles his grandson. Charles collected the evidence, examined it in detail and wrote up the results. Perhaps if I had...”

Captain Flint by Dr Mc Neil
My one claim to fame must be that I was the first person on earth to see the electron spin resonance spectrum of flint. Or, more to the point, I was in the team that actually published the results from these spectra. It could be, of course, that someone else had actually seen the spectrum beforehand, but had dumped it in the waste paper bin of time. We shall never know. I also claim to be the first person to look at a spectrum of a flint sample that had been heated. The two are very different – the first is a jumble of lines which would require considerable time and patience to interpret, the second is one single line. Now, even though I am not Darwin – the only relation any of my Scottish ancestors may have had to flint may be summed up as “skin-flints” - even I could see that there was a possible application in this discovery to archaeology, especially when it was shown that the signal from heated flint changed back to that of the unheated form when in the presence of a radioactive substance.

So, what is flint? Flint is mainly silica, or silicon oxide, to give it its full title. It occurs in large lumps in the ground, apparently in layers without any rhyme or reason to connect them to the local geology. The outside of these lumps is usually whitish in colour, and the inside various shades of brown. It is brittle and can be chipped by a skilled 'knapper' to form a sharp cutting edge. Stone-age man had found this out – so as flint is not destroyed by the weather his flint tools are the very first ones of which we have any record.

In man ways flint is like diamond at a molecular level; there are many parallels between carbon (which forms diamond) and silica. Both form giant molecules in which all the component atoms are chemically bonded together. It is these bonds which create the conditions under which electron spin resonance works, for there is no such thing as a perfect diamond or a perfect flint.

Some of the bonds do not link up. It is these 'broken' bonds we detected. When heated, these broken bonds form a more ordered pattern; radioactivity makes for disorder again. So if stone-age man heated his flint (it makes it easier to work, I am told), then dropped it onto a very weakly radioactive ground, slowly but surely the signal will change. If we can measure the relative sizes of the two signals and if we know the amount of radioactivity which will completely change the heated signal to the ordinary one, then we will know how much radioactivity the flint has been subjected to from the moment it was dropped until now. All we need to know then is how radioactive the earth in which it was buried in has and – hey presto! We can find how long ago it was dropped.

How did I get involved in all this? It was a summer school for the Open University held at Reading University where I was a demonstrator in chemistry practicals for a week. I got the job because a friend of mine was a lecturer for the O.U, but could not attend the summer school for personal reasons, she gave me the application form. It appears that this form differed from the standard form in some way, I learnt later, in that it gave a preference which I did not deserve. Anyway, I met a chemicoarchaeologist there who wanted to examine flint using electron spin resonance spectrometry, and it so happened that I was working (part-time unpaid) at Leicester University using this method to study diamond. The rest, they say, is history.

Sadly, having made the discovery, we were not able to develop it. Leicester University did not have the right equipment to measure the radioactivity accurately enough, so the project was transferred to Queen Elizabeth college, London University, whilst I went on examining grain samples, ending in helping a study of Lindow man: but all that is another story.

I went back to Leicester University recently. The building which once housed the research chemistry labs is now the archaeological block – which might be appropriate, if there were any memorial to our ground-breaking work (forgive the pun). There is not. I was reduced to looking at the place where our spectrometer had been through an office window. Of the others in the team, the professor I worked for has been dead these many years, whilst the chemico-archaeologist has retired to Wales where he lives in poor health. I have not kept up with any developments, but I do know that electron spin resonance spectroscopy has been used to date ancient artefacts.

As I gazed through that office window an archaeologist passed by. He had no knowledge at all of what had happened in that room. I suggested that a memorial would be appropriate. He agreed; we will get a blue plaque...One day.

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