When this governor was started, the trouble absolutely vanished. The engine ran with perfect uniformity while the load was constant. I use the adjective “perfect” advisedly, for the governor slide was as motionless on the spindle as if it were screwed tight, and the governor proved to be the most sensitive possible index of the variations of speed. When the belt was thrown off to the loose pulley the engine ran idle. The counterpoise then rose promptly but gently to its fixed highest position, and stood there motionless until the belt was thrown on and the hammers were started, when it moved as gently but promptly down to its lower position and stood there again motionless so long as the hammers were running. We could not detect by the eye the variation in speed that caused this action of the governor. The heaviest load on the engine, however, was dragging rapidly the two tables loaded with stone. This caused the governor to settle still further, but always the motion of the engine seemed to be the same so far as I could detect. The surface produced on the stone left nothing to be desired. The machine cut true planes, free from any windage, and the surfaces were left so smooth that the rubbing-machine had but little to do, and kept up with the cutting-machine very easily. The governor fascinated everybody who witnessed its operation. [Illustration: The First Porter Governor.] I first made the drawing for the governor with the weight hanging to the slide. Mr. John McLaren, a machinist who had done good work for me, when I showed it to him said, “Why don’t you turn your weight upside down and put it between the arms?” I was not long in acting upon this suggestion, and that made the Porter governor complete. I had it described and illustrated in the _Scientific American_. They took a photograph of it as photographs were taken in those days--that is, they sent their artist up to make a sketch of it, and this sketch (shown here) and description will be found in the _Scientific American_ of October 9, 1858. This governor has never been changed by me except in the shape of the counterpoise. I believed the mathematics of my advisers to be sound, and that the perfect action of the governor was obtained entirely by the long driving-joint, which I supposed would have enabled the 36-lb. balls at 50 revolutions per minute to do just as well as 1-lb. balls at 300 revolutions, but I never tried the experiment.