CHT331723 Letter inviting the Danish Government to send experts to Paris to determine at an international conference the metric system, June 1798 (pen, ink & paper) by French School, (18th century); Archives du Ministere des Affaires Etrangeres, Paris, France; (add.info.: perhaps the first international scientific conference assembled experts from France and her allies and neutral states (Denmark, the Netherlands, Spain, Switzerland and several Italian states) to work out a common and universally acceptable system of measures and weights;); 穢 Archives Charmet; French, out of copyright.