Constructing an envelope involves several steps: cutting the paper into the correct form, folding the flaps, sealing three of the flaps, and applying adhesive to the top flap that the user can seal at a later time. Until the 1840s, laborers preformed these steps by hand. Stationery store clerks used tin patterns to cut envelope sheets that they would then fold and seal. The labor-intensive process made the envelopes costly. If the consumer did not find that expense too prohibitive, there was still the cost of mailing a letter with an envelope to consider. Prior to 1847, the number of sheets of paper in each letter factored directly into the cost of mailing. When the post office calculated the new rates by weight only, demand rose for envelopes that covered and protected the letter.
Changes to postage rates in the mid-nineteenth century not only encouraged more people to send mail but also spurred a new industry in the mass production of envelopes. During the second half of the nineteenth century, inventors tackled the steps of mechanically folding and sealing envelopes.
- Benjamin, Maynard H. The History of Envelopes. Alexandria, VA: Envelope Manufacturers Association, 1997.
- Pope, Nancy A. “Envelopes in the Machine Age.” En Route, April-June 1997.
Lynn Heidelbaugh, National Postal Museum