2–8 September 1833

No sailing still, but sitting still. I went to the railroad and saw Rocket and Goliath and Pluto and Firefly and the rest of thatvulcanian genera- tion. Mr. Perkins says they should not go faster than fifteen miles the hour. It racks the engines to go faster. There are thirty locomotives upon the road. These only have the circulators. There is no such thing as latent heat. The thermometer indicates all the heat that is present. Only when the particles of the water expand in vapor the particles of the heat expand also. High pressure steam-engines are safer than low.