Abstract
Although by the time you read this we shall be well into autumn and we all will be back at work again, I am writing this in the warm days of August when everyone else seems to be away. The main event of the last week was the meeting of the International Measurement Confederation (IMEKO) Council in London and the excellent but slightly unexpected decision to hold the 2018 World Congress in the United Kingdom. There were strong bids from Hungary and Germany, but our delegation led by Ken Grattan had put in a great deal of effort that finally paid off. Belfast which is to be the host city also sent a couple of very articulate and personable young women to extol the delights of the city and to answer any detailed questions there might be. Kate Davis did a great job of shepherding the delegates most of whom were abroad and made sure that the arrangements ran smoothly. Although there has been a great deal of effort put in so far, it is nothing by comparison with the detailed planning and preparations that now begin. 2018 seems to be a long way ahead, but the time will fly!
We held a dinner for the Council in the Glaziers Hall on the evening before the meeting, and David Kent as this year’s Master of the Worshipful Company of Scientific Instrument Makers elucidated for the group the mysteries of the City Livery Companies and their main function today as supporters of charitable causes.
The dinner was held in the splendid dining room overlooking the Thames; we had a great view of the City and of London Bridge itself to our right. The present bridge was opened by the Queen in 1973, but we were able to explain to the delegates that it was only the last in a long succession of bridges joining Southwark to the City of London. Its immediate predecessor, the Rennie bridge of 1831, was made of Dartmoor granite, and by the 1960s was no longer wide enough for the flow of traffic and was in urgent need of replacement; regular surveyors’ measurements had shown that the combined effects of the weight of the structure and the vibrations of the traffic were causing the piers of the bridge to settle gently into the Thames mud. It was therefore clear that the bridge had to be replaced.
Then, through a brilliant piece of entrepreneurship on the part of one of the City Councillors, Ivan Luckin, the old granite bridge was sold for US$2.5m to the American owner of McCulloch Oil. It was disassembled stone by stone, each carefully marked, and shipped to Arizona where it was reconstructed as bridge over Lake Havasu where it can be visited today.
The 1830 bridge had itself replaced a much earlier mainly wooden structure that was in part more than 600 years old and which had survived the great fire of 1666 only because the City side had been seriously damaged in a fire a little earlier. This is of course the bridge that is commonly seen in old prints of London flanked on either side with rickety houses and businesses that looked as if they were about to collapse into the river. Some of them did.
The safe construction of towers and bridges on the scale that we see them today crucially depends on the array of sophisticated laser-ranging technologies that are now available. They allow a speed and precision of surveying that were unthinkable even 30 years ago. The surveyors who oversaw the construction of London’s ancient structures were both careful and very good at their jobs. Very few of their structures fell down!