science · 10 June 1902 · 122 years ago
In 1902, the first U.S. patent for a window envelope was issued to Americus F. Callahan of Chicago, Ill., which he called the outlook envelope (U.S. No. 701,839). He leased the patent to the Envelope company of Springfield, Mass., which began its manufacture in Jul 1902. This style of envelope was able to save expense of printing or labour of addressing, and in addition save time in preparing the message for dispatch when the customary addresses are already on the letter paper itself.
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