Some time after the engine was started I received a line from the Postmaster saying they were much disappointed in it. They expected a gain in economy, but they were burning more coal than before, also that the engine pounded badly. I went to New York to see what the matter was. The engine seemed to be working all right except for the knock, so I made my way down to the sub-cellar. There was nothing there but the boilers and the engineer’s desk. On the cellar stairs, after I had shut the door behind me, I heard a loud sound of escaping steam. The boilers were under the middle of the building; a four-inch steam-pipe ran from them a distance of about eighty feet, suspended from the ceiling, to a point under the engine, then turned up through the floor to the under side of the steam-chest. The exhaust pipe, of the same size, came from the engine through the floor and was carried parallel with the steam-pipe to the middle of the building and upward through the roof. The two pipes were about eighteen inches apart, and in the vertical portions under the ceiling they had been connected by a half-inch pipe having a globe valve in the middle of its length. The valve-stem was downward and the valve set wide open. The noise I heard was caused by the steam rushing through this pipe. I computed that about as much steam was being thus blown away as was used by the engine. My first impulse was to call upon the Postmaster and tell him what I had found, but I decided not to bother him. I could not reach the valve to close it, but discovered a box used for a step to an opening in the wall, so I brought that out and standing upon it was able to close the valve; then the noise ceased and I put the box back.