6 CONTENTS 



PAGE 



2. PRESSURE KELATIONS 44 



A. Deductions from the characteristic equation . . 44 



B. Empirical relations and molecular weight ... 46 



3. TEMPERATURE KELATIONS 48 



A. The critical coefficient . 48 



B. Boiling point 5 



1. Additive relations 50 



(a) Equal boiling points of isomers ..... 52 



(6) Increase of boiling point with molecular weight . . 52 

 (c) Equal differences in boiling point for equal differences 



in composition ........ 53 



(cT) Compounds of more or less volatile elements . . 53 

 (e) Molecular weight and boiling point . . -53 



2. Constitutive influences 54 



(a) Rise of boiling point under the influence of strong 



affinities . 55 



Accumulation of negative atoms or groups . . 55 



(fc) Influence of molecular symmetry 56 



4. CALORIMETRIC KELATIONS ....... 57 



A. Latent heat of evaporation 57 



B. Specific heat 60 



1. Specific heat of perfect gases ...... 60 



2. Specific heat of liquids ........ 63 



3. Difference between specific heat of liquid and vapour . . 65 



4. Specific heat of solids ........ 66 



(a) The law of Dulong and Petit 66 



(/3) Application of specific heat to determine atomic weight 68 



(7) Additive character of the specific heat of solid bodies . 69 



(8) Theoretical indications ....... 70 



5. CAPILLARITY AND SURFACE TENSION . . . .71 



A. Observations 71 



B. Molecular weight and surface tension . . . .72 



Surface tension ......... 73 



Influence of temperature ....... 74 



Relation to molecular weight ...... 75 



C. Theoretical relations 76 



