Goes to London 80 Returns to Glasgow 80 Appointed Instrument-maker to the University 81 Opens a Shop in Glasgow 81 His Friends and Patrons 81 Professor Robison's Remarks on Watt's personal Character 82 His industrious and studious Habits 82 His Attention first directed to Steam 83 Experiments on High-pressure Engine 83 Repairs an Atmospheric Model 84 Experimental Inquiry consequent on this 84 Its Results 84 Observes great Defects in the Atmospheric Engine 85 His first Attempt to improve it 85 His early Experiments on Steam 87 Discovery by Experiment of the Expansion which Water undergoes in Evaporation 90 Discovers the latent Heat of Steam 91 Informed by Dr. Black of the Theory of latent Heat 93 His Improvement not due to Black 93 CHAP. IV. EXPOSITION OF PHYSICAL PRINCIPLES. Construction of Thermometer 98 Method of graduating it 99 Freezing and boiling Points 99 Latent Heat of Water 101 Quantity of Heat necessary to convert Ice into Water, first noticed by Dr. Black 101 Examination of the analogous Effects produced by the continued Application of Heat to Water in the liquid State 102 Process of Boiling 104 Reconversion of Steam into Water 104 Conversion of Water into Steam 105 Latent Heat of Steam 107 Boiling Point varies 108 Different in different Places 109 Inquiry whether a Diminution of Pressure will produce a corresponding Effect on the boiling Point 112 Table showing the Temperature at which Water will boil under different Pressures of the Atmosphere 113 Mechanical Force of Steam 115 Facts to be observed in 117 CHAP. V. FURTHER DISCOVERIES OF WATT. Watt finds that Condensation in the Cylinder is incompatible with a due Economy of Fuel 119 Conceives the Notion of condensing out of the Cylinder 120 Discovers separate Condensation 121 Invents the Air Pump 123 Substitutes Steam Pressure for Atmospheric Pressure 123 Invents the Steam Case, or Jacket 124