The Burd High Compression Ring Company of Rockford, Ill., supplied the piston-rings out of stock made up for the Hall-Scott line of standardized aeroplane engines, for which it had perfected a piston-ring. The Aluminum Castings Company of Cleveland supplied the die-cast alloy pistons, and machined them up to grinding, as they had been engaged in making them for several years for the Hall-Scott line of standardized aviation engines. The Rich Tool Company made the valves. [Illustration: The Martin bomber. This plane is equipped with two Liberty engines and has many long-distance records. It flew from Pittsburgh to Washington, a distance of 175 miles, in 1 hour and 15 minutes. It also flew from the Atlantic to the Pacific.] The Gibson Company of Muskegon made the springs. The Packard Company made the patterns and several dies in order to obtain drop-forgings of the proper quality. It also machined the crank-shafts. After the preliminary tests passed by the 8-cylinder engine, August 25, 1917, Government Inspector Lynn Reynolds said “that the design has passed from the experimental stage into the field of proven engines.” The machine was tested at Pike’s Peak, Colorado, for altitude in August, 1917. Reports from the battle-field decided the board to build 12-cylinder engines. Thereupon standardized parts made interchangeable for all types of Liberty engines were detailed, and orders placed with the various firms named to build the same. Production was started on a large scale. On October 17 the production of the Liberty motor started, over six months after we entered the war. The delivery of the first Liberty 12 was made on Thanksgiving Day, 1917. One of the unrecorded incidents of this period concerned the “scrapping” of $400,000 worth of semi-finished parts of an automotive aircraft engine, which was assumed O. K., and parts had been ordered for 250 motors. It was actually in production at the time Hall and Vincent were ignoring practically all its features and “laying out” the designs for the Liberty 8 and Liberty 12. It had never been tested in a plane, and its design and all its parts were rejected. Owing to the slowness of production due to the new gigs, dies, tools, etc., necessary to build the engines, much criticism was directed at the lack of shipments of Liberty engines for army air service in the winter months of 1917. Charged with the necessity of protecting the American army transport, the Navy Department had first call on all air-service equipment. As a result it received the first Liberty 12’s turned out. These were installed in navy aeroplanes, where they did good work.