Bangladesh, April 24 -- There is a building in London, just north of the Thames, where for more than seven centuries a specific kind of work has been done that almost no one thinks about. In the Goldsmiths' Hall, craftspeople sit at benches with instruments that weigh and assay metal. When a refiner or a jeweler brings an object in to be marked, the assayer scrapes a trace of material from it, tests the purity, records the result, and stamps the object with a small symbol. The symbol certifies that an independent party, paid only for the accuracy of the test, has verified what the object contains.
The London assay office was established in 1300. It has been continuously operating for seven hundred and twenty-six years. During that time, mo...