During the first two or three weeks the steam pressure was kept up to 75 pounds, as intended, and I was able to get diagrams cutting off quite early, which were then erroneously supposed to show superior economy. But when all the steam-eaters had got in their work the pressure could not be maintained much above 40 pounds, and for that exhibition the day of fancy diagrams was over. Gwynne & Co. showed a large centrifugal pump driven by a pair of engines which always brought the pressure down at the rate of a pound a minute. They were not allowed to run longer than fifteen minutes at a time, but it took a long time after they stopped before the pressure could be got up again even to 40 pounds. Whenever I took a diagram somebody was always standing ready to take it away, and so among my mementoes I have been able to find none cutting off earlier than the one here represented. On the wall at the back I hung the largest United States flag I could find, with a portrait of President Lincoln. This seems all that needs to be said about the photograph and the diagram. [Illustration: INTERNATIONAL EXHIBITION, UNITED STATES DEPARTMENT 1862 DIAGRAM TAKEN FROM 1862 THE ALLEN ENGINE BY THE RICHARDS INDICATOR. ENGINE, 8 INCHES BY 24 INCHES, REVOLUTIONS PER MINUTE, 150. SCALE, 40 LBS. TO THE INCH.] But what was the matter? I will clear the way to answering this question by relating the following incident: Six months later, with a feeling of bitter disappointment, I contemplated my engine standing alone where the place had been thronged with surging life. All the other exhibits had been removed. This was left in stillness and desolation, and I was making up my mind to the necessity of shipping it home again, its exhibition to all appearance absolutely fruitless--a failure, which I was utterly at a loss to comprehend, when I had a call from Mr. James Easton, the same man who had first welcomed me in England. His firm had perhaps the largest exhibit in the Machinery Hall, of a waterfall supplied by a centrifugal pump, and they had been frequent observers of the running of my engine, which was quite near them. Mr. Easton bluntly asked me if I thought my engine could be run 50 per cent. faster or at 225 revolutions per minute, because they had concluded that it could be, and if I agreed with them they had a use for it themselves. Under the circumstances I did not hesitate long about agreeing with them in respect to both ability and price, and the sale was quickly concluded. I noted an entire absence of any disposition to take an undue advantage. Mr. Easton then told me that they were troubled with lack of power every afternoon when the foundry blower was on, and had long wanted to drive this blower independently. It needed to make 2025 revolutions per minute to give the blast they required, and they had planned to drive it by a frictional gearing, nine to one, if my engine could run at the necessary speed. So