The second engine had been built by a prominent iron works in New York, from Mr. Allen’s drawings, for a paint mill in South Brooklyn. Both names I have forgotten. Mr. Allen took me to see this engine soon after I came home. It had then been running for a year or more, and had given high satisfaction. Its local influence was found quite valuable to us. This engine is memorable for the following reason: Ten years afterwards, while building engines in Newark, I received from Mr. Mathieson, manager of the National Tube Works in McKeesport, Pa., a letter containing an invitation to make him a tender for two large Allen engines, the largest I had yet attempted, and which resulted in my building these engines for him. After they were successfully running, Mr. Mathieson told me how he came to write me. He said he was the superintendent of the iron works in New York in which Mr. Allen had this engine built, and was very much impressed by its advantages, especially after he saw it in operation; and in planning this mill these engines seemed to be just what he wanted. [Illustration: Sectional and Front Elevations of One of the Two Pairs of Porter-Allen Engines in the Colt Armory, Hartford, Conn.] [Illustration: Porter-Allen Engines in the Colt Armory, Hartford, Conn. Front View] [Illustration: Porter-Allen Engines in the Colt Armory, Hartford, Conn. Rear View] [Illustration: Sectional and Side Elevations of One of the Two Pairs of Porter-Allen Engines in the Colt Armory, Hartford, Conn.] In preparing for the engine manufacture one of my first aims was the production of true surface plates for finishing my guide-bars, cross-heads, valves, and seats, and cylinder and steam-chest joints, all of which I made steam-tight scraped joints requiring no packing. This was a new departure in steam-engine work in this country. I fancied myself an expert in the art, but found out that there was one degree at least that I had not taken. I designed several sizes of surface plates, intended primarily to fit the guide-bars of the engines, and also straight edges 6 feet in length by 2¹⁄₂ inches wide. These are represented in the accompanying cuts. [Illustration: Surface Plates Designed by Mr. Porter.] I found still working in my governor shop a man named Meyers. He was the best fitter I ever had; had fitted every governor made in my shop, the little engine or the parts of it that I took to England, and long before had fitted my stone-cutting machine in Mr. Banks’ shop. This man I taught all I knew about the art of producing true planes by the system of scraping, and he produced surface plates and straight edges that seemed to me quite perfect.