Stone (unit) - Metric Stone

Metric Stone

Although the advent of the metric system spelt the demise of the stone as a unit of measure, the stone was used in some early discussions and implementations of the metric system. In his Philosophical essay written in 1668, John Wilkins proposed a system of measure whose unit of length, the standard, was approximately one metre and whose unit of mass was the mass of a cubic standard of rainwater (which would have been approximately 1000 kg). He proposed that one tenth of this mass (100 kg) should be called a stone. In 1791, a few years before the French Revolutionary Government agreed on the metre as the basis of the metric system, Thomas Jefferson, in a report to Congress proposed that the United States should adopt a decimal currency system (which was adopted) and a decimal-based system of measure (which was not adopted). Jefferson's proposal for units of measure included a "decimal" pound equal to 9.375 ounces (265.8 g) "customary" ounces and a "decimal" stone of 10 "decimal" pounds or 5.8595 pounds (2.6578 kg).

Neither Wilkins' nor Jefferson's proposals were adopted, but in the Netherlands where the metric system was adopted in 1817, the pond (pound) was set equal to one a kilogram and the steen (stone) which had previously been 8 Amsterdam pond (3.953 kg) was redefined as being 3 kg.