Published with permission of Hugh Jones:
In a message dated 1/4/2015 7:17:42 P.M. Eastern Standard Time, aimssec@aol.com writes:
Dear Mark,
Happy New Year to you.
I went to Finsbury Park this morning assist my youngest daughter to become more familiar with measurement stuff (although she has been doing peripheral measurement tasks for the last 10 years, including laying out the original version of the Cardiff Calibration course on Lloyd George Avenue). Sorry I did not offer you the opportunity to join us, but ...
What we found was a brilliant exercise in measurement detection. Even Ella seemed to be mildly impressed.
We started from the nail at the Manor House Gate end and laid out 10 x 49.9m lengths plus another metre. What I saw, just 10cm further on, was the nail marking the south end of the course. It was there the whole time (since I banged it in maybe 7 or 8 years ago, assisted by another of my children - probably Coral, soon to be 23).
We were looking for it in the wrong place. On the original documentation I showed that south nail to be in line with the south face of a waste bin just alongside on the left (Seven Sisters Road side). We had been looking for it relative to that 'same' waste bin, but the end of our taped measurement was 4 or 5m further on.
I found the nail thanks to the discipline of the taping exercise (very studiously followed by Ella). Then I saw, eyes left, that there was a faded patch of grass where something had once been implanted. I am sure that this was the previous position of the waste bin (the patch was of the right dimensions, circa 40cm x 40cm). And there were still some faint traces of the green spray paint that I used to mark around the nail all those years ago.
So the calibration course remains intact (but you may still find it difficult to find that nail).
And what about the missing ('extra') 100mm revealed by our taping exercise?
In London it was 1C this morning (hats on to Ella for sticking by the appointment in such conditions). Applying the correction factor for the expansion/contraction of steel: 19C x 0.0000115/m/degC = 0.0002185/m. Then we multiply by the length of the calibration course, 500m, and get: 0.109m. So the measurement I did with Coral many years ago was within 9mm of that I did with Ella this morning. Alternatively, converting our taped 500m length to directly correct for temperature, I see it gives me a length of 499.991m ('same difference').
I am sure you sense my underlying feeling of exhilaration even all these hours later and even though there is no call for it. We all know our methods are reliable, so why do we need reassurance? Dunno, but what Ella and I did today helped to underline the robust quality of our work (I mean the work of all conscientious course measurers, anywhere).
And you personally can now calibrate again in Finsbury Park (as long as you can spot that south nail).
Very best,
Hugh
Pete's reply (he was sent a copy of Hugh's message)
Dear Hugh,
Your message brought back a specific memory of discomfiture. I was measuring the route of the Cleveland Marathon decades ago, and using a calibration course which I had laid out several years previously. I found the paintmark and the nail at the west end and used my bike's usual calibration to look for the eastern nail. To my consternation I could not find it.
After half an hour of scratching my head I discovered that the western mark was not my mark - it was someone else's. I looked for and found my proper mark and everything fell into place. It was a huge relief, as I was 130 miles from home and working alone.
With all of the hundreds of courses I've measured I am fairly certain that I've made some undiscovered mistakes, but I don't know which ones. Since I stopped measuring several years ago it seems unlikely that any of my mistakes will ever be discovered.
I prefer to be thought of as perfect although experience has shown the contrary to be true.
Thank you for the message. I well remember the initial horror and the final relief.
Best regards, Pete
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