On a table between the railing and the head of the engine I showed mahogany sectional models of the valves at one end of the cylinder in the engine exhibited, and of the now well-known Allen slide valve, with double opening for admission made by a passage over the exhaust-cup.
The Richards indicator is seen placed on the cylinder midway of its length, and connected by pipes with the ends over the clearances, so that in the familiar manner by means of a three-way cock the opposite diagrams could be taken on the same sheet. After a few days’ use I mistrusted that the lead lines were not correctly drawn, and I took away these pipes, placing the indicator on the cylinder itself, at the opposite ends alternately. The diagrams then taken showed that the error from transmission through these pipes had been even greater than I had feared. I have, of course, employed the close connection ever since.
This identifies the time when the photograph was taken. It must have been within a few days after starting.
The center of the eccentric coinciding with the crank, as already stated, and the center line of the link being in the same horizontal plane with that of the engine, I was able to take the motion of the paper drum from the sustaining arms of the link instead of from the cross-head. This was very convenient.
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.
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 this most peculiar and exceptional opportunity for its application, absolutely the only chance for its sale that had appeared, and that at the very last moment, prevented my returning home in disappointment. It is hardly necessary to add that the engine proved completely successful. I shall refer to it again.
The point of the incident is this: It established the fact, the statement of which otherwise no one from the result would credit for an instant, that, from the afternoon when the black and averted looks of my loom exhibitors were changed to smiling congratulations down to the close of the exhibition, the engine never once had a warm bearing or was interrupted for a single moment. It was visited by every engineer in England, and by a multitude of engine users, was admired by every one, and won the entire confidence of all observers in its speed, its regulation, and the perfection of its diagrams; and yet in all that six months not a builder ever said a word about building it, nor a user said a word about using it; and, as week after week and month after month passed without a sign, I became almost stupefied with astonishment and distress.
The explanation of this phenomenon was entirely simple, but I did not know it, and there was no one to even hint it to me. I was among a people whose fundamental ideas respecting steam-engines were entirely different from those to which I had been accustomed, and I knew nothing about them, and so could not address myself to them. In the view of every Englishman a non-condensing engine was rubbish. Those which were made were small, cheap affairs, mostly for export. Neither a builder nor a user could regard a non-condensing engine with the slightest interest.