General effects. Arbitrary choice of one of these effects to define the thermometric condition of a body. Conventional adoption of a thermometer. Definition of temperature.
Dilating Effects.
Definition of the co-efficients of linear, superficial, and cubic dilatation. Approximate relation between the numerical values of these three co-efficients. The value of the co-efficient of dilatation depends upon the thermometric substance and the temperature selected as the zero point. It becomes nearly independent of the zero point when the co-efficient is very small.
Relation between volume, density, and temperature. Linear dilatation of solid bodies. Ramsden’s instrument. Cubical dilatation of liquids. Dulong and Petit’s experiments on mercury. Discussion. Regnault’s experiments.
Cubical dilatation of solids and of other liquids when that of mercury is given.
Relations between the volume, density, and elasticity of a gas, and its temperature.
Cubical dilatation of gases. Experiments of Gay-Lussac, Rudberg, and M. Regnault. Advantage of varying the methods of experimenting in these delicate researches.
Methods based upon the changes of volume under a constant pressure, and upon the changes of pressure for a constant volume.
The disagreement of these two methods is due to deviations from the law of Mariotte.
The constancy of the co-efficients of dilatation previously defined is only approximately true.