Keywords: Arago kilogram.jpg metric standards used by the United States It was procured by the US from France in 1821 to serve as primary standard for metric weights It was made of platinum by the French firm Fortin and certified by French physicist Francoise Arago to be within 1 mg of the Kilogram of the Archives the French prototype standard defining the kilogram In 1866 the US Congress legalized but did not require the use of metric measures in the United States It served as the primary US standard for the kilogram until 1889 when the US received the current standards K4 and K20 from the BIPM The Arago Kilogram is now part of the NIST museum collection US National Institute for Standards and Technology Bethesda Maryland date Downloaded 2013-01-17 from http //museum nist gov/object asp ObjID 20 Arago Kilogram Room 3 Weights and Measures NIST Virtual Museum website US National Institute for Standards and Technology No copyright attribution accompanied this image http //www nist gov/public_affairs/disclaimer cfm Disclaimer on NIST site With the exception of material marked as copyrighted information presented on these pages is considered public information and may be distributed or copied author PD-USGov Uploaded with UploadWizard Kilogram |