( 1029 ) 



XXII. — On the Foundations of the Kinetic Theory of Gases. III. 



By Professor Tait. 



INDEX TO CONTENTS. 



Introductory, 1029 



Part XV. Special Assumption as to Mole- 

 cular Force, . . .1031 

 „ XVI. Average Values of Encounter and 



of Impact, . . . .1031 

 „ XVII. Effect of Encounters onFreePath, 1035 

 „ XVIII. Average Duration of Entangle- 

 ment, and consequent Average 

 Kinetic Energy, . . . 1037 



PAGE 



Appendix — 



A. Coefficient of Restitution less than 



Unity, 1038 



B. Law of Distribution of Speed, . . 1039 



C. Viscosity, 1039 



D. Thermal Conductivity, . . .1040 



I have explained at some length, in my " Reply to Prof. Boltzmann," * the circum- 

 stances under which the present inquiry originated and has been pursued. Of these I 

 need now only mention two : — -first, the very limited time which I can spare for such 

 work ; second, the very meagre acquaintance I possessed of what had been already done 

 with regard to the subject. My object has been to give an easily intelligible investiga- 

 tion of the Foundations of the Kinetic Theory ; and I have, in consequence, abstained 

 from reading the details of any investigation (be its author who he may) which seemed 

 to me to be unnecessarily complex. Such a course has, inevitably, certain disadvantages, 

 but its manifest advantages far outweigh them. 



In August 1888, however, I was led in the course of another inquiry t to peruse rapidly 

 the work of Van der Waals, Die Continuitdt des gasformigen und flussigen Zustandes. 

 This shows me that Lorenz had anticipated me in making nearly the same correction of 

 the Virial equation as that given in the earlier part of § 30 of my first paper. His 

 employment of the result is a totally different one from mine ; he uses it to find a 

 correction for the number of impacts. The desire to make, at some time, this investi- 

 gation arose with me when I was writing my book on Heat, as will be seen in the last 

 paragraphs of § 427 of that book. It was caused by my unwillingness to contemplate 

 the existence of molecular repulsion in any form, and my conviction that the effects 



* Proc. R. S.E., January 1888; Phil. Mag., March 1888. 



t " Report on some of the Physical Properties of Water," Phys. Ghem. Chall. Exp., Part IV. 



VOL. XXXV. PART IV. (NO. 22). 7 R 



