The Courant reports that production of stamped envelopes continues to increase and Plimpton Manufacturing Company

The factory currently had nine stamping or embossing machines that were printing stamps.

1. The machines currently in use at the factory could print 10,000 envelopes per hour. With nine in use, that was 90,000 per hour, or a “rate of 900,000 every ten hours.”
2. Sixteen additional machines were scheduled to be installed. They arrived at a rate of one machine every five days.
3. Each of these new machines could print 75,000 envelopes per hour.

On October 29, 1874, the Courant reported that the Plimpton Manufacturing Company was shipping large numbers of envelopes every day.

The Plimpton Manufacturing Company was working on the completion of the order for 308,000 envelopes today.

1. “The Plimpton company are rapidly getting into full running order. They are constantly increasing their facilities for doing the government work by introducing new machinery.”
2. “The company expects to be able soon to deliver over 500,000 envelopes every ten hours.

Unattributed.  “Government stamped envelopes,” Hartford Daily Courant, October 30, 1874, page 2.