Envelope

en'vel-op, a paper pocket used chiefly for inclosing a letter. It is sealed usually by means of a flap or folded portion, faced at its edge with mucilage. As late as 1845 letters were folded so as to leave an unwritten portion outside for the stamp and address. They were sealed with wax. Envelopes did not come into general use earlier than the middle of the nineteenth century. At first they were made by hand, and were comparatively expensive. Since the invention of special machinery an entire ream of paper is cut into suitable pieces by a single motion of a sharp edged die. The mucilage is applied, the folding is done, and the envelopes are packed, all by machinery. It is estimated that a single machine, well managed, will turn out 50,000 envelopes in a single day. The total consumption of envelopes in the United States is between three and four billion a year. The stamped envelopes sold by the government are made under contract in but one or two factories, where they are guarded with the utmost care. The government furnishes not less than half a billion stamped envelopes annually.