In spite of all efforts and all our good luck, we were not ready to start until a week after the opening day, May 1, and the exhibitors were in despair, for none of them believed that this new-fangled American trap would work when it did start at the frightful speed of a hundred and twenty revolutions per minute, which they had learned from Mr. Clark it was to make. Finally one day after our noon dinner I turned on the steam, and the governor rose at the speed of one hundred and fifty revolutions precisely. It was immediately surrounded by a dense crowd, every man of whom looked as if he expected the engine to fly in pieces any instant. It was not more than two minutes after it started when I saw Mr. Clark coming with his watch in his hand. Some one had rushed to his office and told him the Yankee engine was running away. The crowd opened for him, and he came up to the engine and watched it for some time, walking leisurely around it and observing everything carefully from all points of view. He then counted it through a full minute. At its close he turned to me and exclaimed, “Ah, Porter--but,” slapping me cordially on the shoulder, “it’s all right. If you will run as smoothly as this you may run at any speed you like.” And so the high-speed engine was born, but neither Mr. Clark, nor I, nor any human being then knew what it was that made it run so smoothly. I have since realized more and more what a grand man Mr. Clark then showed himself to be. A small souled man might have regarded the matter entirely from a personal point of view, and been furious at my defiance of his authority. There are such men. I will show one to the reader by and by. Officialism is liable to produce them. I was quite unconscious of the risk in this respect that I was running. I have always felt that I could not be too thankful that at this critical point I fell into the hands of so noble a man as Daniel Kinnear Clark. [Illustration: Mr. Porter’s Exhibit at the London International Exhibition, 1862] CHAPTER VII My London Exhibit, its Success, but what was the matter? Remarkable Sale of the Engine. Thus, as the result of a remarkable combination of circumstances, upon which I look back with feelings more of awe than of wonder, the high-speed system made its appearance in the London International Exhibition of 1862, installed in the midst of the British machinery exhibit, under conditions more advantageous than any which I could have imagined. But the engine had a weak feature: it was wanting in an essential respect, of which I was, and remained to the end, quite unconscious, as will presently appear. Before entering on this subject I will give the reader an idea of what the exhibit was like. The accompanying half-tone from a photograph will, with the help of a little explanation, make this quite real.