Scientists get best measure of physics fundamental

Paris

BENEATH three glass bell jars, in a locked vault in the basement of a highly secure facility outside Paris, sits the world's most important kilogramme.

Ever since 1889, when the General Conference on Weights and Measures (CGPM) made the imperious pronouncement, "this prototype shall henceforth be considered to be the unit of mass", this platinum and iridium cylinder has served as the standard by which all other kilogrammes are measured, from the weights on a high-tech lab scale to the plastic discs high schoolers use in chemistry class.