Translations:The History of Dunhill's Shell/3/en

The American patent application (No. 1,341,418) was prepared and filed before the English patent was granted, between September 19 and October 14, 1918. The American patent was granted more than a year later, on May 25, 1920. Canadian documents were behind the U.S. a year, with application in 1919 and granted in 1921.

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  US Patent Office

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  US Patent Office