"3" . _:b6732792 "Some coppers come already tinned. I didn't buy mine, so they surely were not tinned."@en . _:b6732790 "(countable, dated) Any of various specialized items that are made of copper, where the use of copper is either traditional or vital to the function of the item."@en . _:b6732793 "1907, \u201CInstructions for the Care of Callaud Batteries\u201D, in Journal of the Telegraph, volume XL:"@en . _:b6732792 . _:b6732793 . _:b6732790 . . _:b6732793 "Coppers are not consumed, and their life depends largely on the manner in which they are used."@en . _:b6732791 . _:b6732791 "Coppers are generally good for a year, if the battery is carefully attended [\u2026]"@en . _:b6732791 "1885, General Rules and Regulations Applicable to All Employes of the Chicago and Grand Trunk Railway Company:"@en . _:b6732792 "1890, The Manufacturer and Builder, volume 22, page 83:"@en .