fact was demonstrated, namely, the absolute decarburization of molten crude iron without any manipulation, _but not without fuel_, for had not a very high temperature been kept up in the air furnace all the time this quiet blowing for thirty minutes was going on, it would have resulted in the solidification of the metal in the crucible long before complete carburization had been effected. Hence arose the all-important question: Can sufficient internal heat be produced by the introduction of atmospheric air to retain the fluidity of the metal until it is wholly carburized in a vessel not externally heated? This I determined to try without delay, and I fitted up a larger blast-cylinder in connection with a 20 horse-power engine which I had daily at work. I also erected an ordinary founder’s cupola, capable of melting half a ton of pig iron. Then came the question of the best form and size for the experimental converter. I had very few data to guide me in this, as the crucible converter was hidden from view in the furnace during the blow. I found, however, that slag was produced during the process, and escaped through holes in the lid. Owing to this, I constructed a very simple form of cylindrical converter, about four feet in interior height, sufficiently tall and capacious, I believed, to prevent anything but a few sparks and heated gases from escaping through a central hole made in the flat top of the vessel for that purpose. This converter had six horizontal tuyères arranged around the lower part of it; these were connected by six adjustable branch pipes, deriving their supply of air from an annular rectangular chamber, extending around the converter.