The location was in a narrow space between a side aisle and the wall of the temporary wooden structure, 300 feet wide by nearly 1000 feet long, which formed the machinery hall. The engine was crowded closely by looms on both sides. Here were shown together the first high-speed engine, the first high-speed governor, and the first high-speed indicator. My marine governor could not be accommodated there, and had to be shown elsewhere. I was so much afraid of deflection or vibration of the shaft that I shortened up the length between the bearings and placed the driving-pulley on the overhanging end of the shaft, which for the light work to be done there answered sufficiently well. I showed also the largest and the smallest sizes of my stationary-engine governors. These were belted from the shaft to revolve so as to stand always in positions coincident with those of the governor which regulated the engine. On a table between the railing and the head of the engine I showed mahogany sectional models of the valves at one end of the cylinder in the engine exhibited, and of the now well-known Allen slide valve, with double opening for admission made by a passage over the exhaust-cup. The Richards indicator is seen placed on the cylinder midway of its length, and connected by pipes with the ends over the clearances, so that in the familiar manner by means of a three-way cock the opposite diagrams could be taken on the same sheet. After a few days’ use I mistrusted that the lead lines were not correctly drawn, and I took away these pipes, placing the indicator on the cylinder itself, at the opposite ends alternately. The diagrams then taken showed that the error from transmission through these pipes had been even greater than I had feared. I have, of course, employed the close connection ever since. This identifies the time when the photograph was taken. It must have been within a few days after starting. The center of the eccentric coinciding with the crank, as already stated, and the center line of the link being in the same horizontal plane with that of the engine, I was able to take the motion of the paper drum from the sustaining arms of the link instead of from the cross-head. This was very convenient.