jats:titleAbstract</jats:title> jats:pThe practices of measurement have long been taken as authoritative technologies that travel unusually well and easily across cultural boundaries, and as a sign and cause of the apparent dominance of Western modes of science. Attention to the rituals of measurement and to the emergence of the forms of knowledge that accompanied measurement, notably the sciences of metrology, helps challenge these assumptions. Stories of the silent trade, often located in western Africa, and of the ritual origins of measurement, developed within anthropology and conjectural history, can be used to explore how measurement practices traveled and changed. In particular, the work of Marc Bloch as the preeminent historian of ceremony and power can help illuminate the relation between the historical geography of metrology and the scope of the sciences. His brilliant analysis of the royal ritual of “cramp rings” and its fate provides an important example and precedent for comparably ceremonial and culturally significant episodes in the long history of the science of measurement.</jats:p>