Worldwide trade needs metrology

1 Introduction Trade certainly is one of the basic characteristics of any human society. It dates back to the dawn of man-kind and teaches peaceful relations between partners who are, of course, each seeking their own advantage.The possible geo-graphic extension of trade depends upon the technical means of transportation. Even today we know of the ancient silk-road between China and Syria through which so-far unknown commodities came to Europe, and of the courageous voyages of Christopher Columbus, Vasco da Gama and others, who brought exotic goods with them. Indeed, sugar has always played a prominent role in what could be called the worldwide trade. After sugar cane had already been known in India for several 1000 years, methods for refining with the endproduct of a sugar loaf were developed in Persia as early as 600 B.C. In the 13th centu-ry the crusadors brought cane sugar to Europe, but it remained for several hundred years an expensive luxury, despite cultiva-tion in large plantations in Brazil and elsewhere. After the discovery of sugar beets and their cultivation by Andreas Marggraf in 1747, the price went down and sugar became a constituent part of human nutrition all over the world. Medical science today even assumes that the observable change of human habitus is partly due to the consumption of sugar. Today, the annual world-production of sugar amounts to 120 million t, which means about 20 kg per capita. There is no doubt that sugar is an out-standing example of worldwide trade, but does it have a special relation to metrology, the science of measurement? The answer is “yes”, and this is shown briefly. Contrary to many other commodities, the trade value of a sugar delivery is not only defined by the usual quantitative measurement methods like counting, weighing or dimensional measurements. Apart from chemical methods for the determination of certain quality parameters the sugar content of a solution in water, which is the usual form of a sample, can only be measured sufficiently accurate by using physical methods like polarimetry, refractometry and densitometry. It was Alexander Herzfeld, the founder and first president of the “International Commission for Uniform Methods of Sugar Analysis” (ICUMSA), who suggested the standardization of polarimeters by means of internationally-certified standard quartz plates and so initiated the link between sugar trade and high-precision metrology. Even after 100 years, with many changes in trade and science, his endeavor provides the solid base for an important part of world trade.