Directly after we got running I received a letter from William R. Jones, superintendent of the Edgar Thompson Steel Company, running a rail mill recently started at Braddocks by Carnegie Brothers, saying that they were in need of an engine to drive a circular saw at a very high rate of speed to cut off steel rails cold. They had been recommended by Mr. Holley to get one of mine, and if I could furnish a suitable engine immediately he would order it. Fortunately I could. While I was building engines in Harlem, the city of Washington, D. C., went into the system of wooden pavements, and the contractor obtained an engine from me for sawing up the blocks. About the very time I received Mr. Jones’ letter I had learned that the wooden pavement system was being abandoned in Washington for asphalt and the sawing-mill was closed. I at once wrote to the contractor making him an offer for the engine. I received by return mail a reply accepting my offer, and adding most complimentary words concerning the engine. These I remember closed by saying that his admiration of it was such that if he were able he would put the engine in a glass case and keep it there as long as he lived. The engine proved just right for Mr. Jones’ use. I went myself to Braddocks to see it started. All were much interested in the governor action, I as much as any one, for I had never before seen this particular application of it. In sawing through the head and web and bottom flange of the rail, the width of section being cut varied continually, and the gentle rising and falling of the counterpoise, adjusting the power to the resistance, while the engine kept, so far as the eye could detect, a uniform motion, had about it a continual fascination. The success of this engine brought me several orders for governors, the most important of which was one from Mr. Jones himself for governors and throttle valves for his blooming mill and rail-mill engines. I got up for him balanced piston valves which operated perfectly. In iron valves and seats of this character it had been found, where the steam contained primed water, that their edges wore rounded, and their action in regulating the motion became less and less satisfactory. I knew that these boilers primed badly, and avoided this defect by setting brass rings in the edges. The following illustrations show this regulating valve which I designed and made in two sizes. [Illustration: Mr. Porter’s Regulating Valve.] The brass liner for the lower seat was passed through the upper seat by being made thinner than the upper liner. Those for the valve were made ¹⁄₈ inch too long, and guttered in the lower edge. They were then driven down by a set and sledge on an anvil. By going around them three times the lower edges were spread out to fill the chamfer, and the flanges brought down to their seats. Those for the lower valve were put in in halves. [Illustration: WILLIAM R. JONES] CHAPTER XXIII