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Show The Standard Yard. In 18S5 there was completed a gun-metal gun-metal bar, representing the imperial standard yard of Oreat Britain. It was found!' however, that standards mad jf bronze or gun metal were liable to an appreciable alteration in length through molecular and other changes, and accordingly a few years ago, the Imperial standard was replaced with a bar of Irldlo-platlnum, consisting of 90 per cent, platinum and lo per cent. Iridium. Thlspcw alloy Is less alterable than bionze. The new bar was made of an X-shaped cross section to combine rigidity with comparative lightness, and for one year It was subjected to a series of tests and measurements Involving In-volving the most refined 'methods known to science. The bar has maiked on it the length both of the standard yard and of the standard meter. Harper's Har-per's Weekly. |