Temperature and Molecular Attraction. 93 



laiv leaves no room whatever for doubt that the relation of 

 Kleeman is not supported by the facts. The variation in the 

 constant of Kleeman's equation cannot be attributed to the 

 data, which are far too accurate to permit of the variations 

 noted, and it is not due (as Kleeman supposes) to the influence 

 of temperature upon the attraction. The possible influence 

 of temperature upon chemical affinity has been specially 

 studied by the author* for the reaction H 2 + 0=H 2 0, and 

 the evidence is overwhelmingly against the idea that tempe- 

 rature changes the chemical attraction. The constancy of 

 the results detailed in Table I. is itself evidence that tempe- 

 rature is without influence on molecular attraction, and this. 

 fact will appear more clear when the extensive discussions 

 cited are considered. The probable mutual relation of tem- 

 perature and molecular attraction is discussed in Part III. 

 of this article. 



Part IL— The Relation of Dieterici, X=CRT ln~ . 



In this relation C is a constant, nearly, but not quite, the-- 

 same for all substances ; R is the usual gas constant ; T 

 denotes absolute temperature; the other symbols are as- 

 given before. 



This relation was proposed and discussed by Dieterici f 

 and later by RichterJ, and has been thoroughly investigated 

 by the author §. Kleeman investigated this equation ||, using 

 data (which data have since been subject to some corrections 

 by Young) from an earlier paper by the author, and has 

 overlooked entirely the discussion of this equation by the 

 author. (Perhaps I was at fault in publishing these phvsical 

 relations in journals devoted mainly to chemistry.) I there- 

 fore republish in Table II. a summary of the results obtained.. 



In this table all values of C differing by more than 2 per 

 cent, from the average value of the uncrossed results shown 

 at the top of the column are marked with an asterisk above 

 and to the right. All values of C differing from this average 

 value of C by more than 1 per cent, are marked with a plus 

 or minus, above and to the left, to show the nature of the 

 divero-ence. • 



© 



* Trans. Amer. Electrochemical Soc. xiv. p. 35 (1908). 

 t Ann. der Phj/sik, (4) xxv. p. 569 (1908). 



% Inaugural-Dissertation, Eostock, 1908, " Ueber die imiere Ver« 

 dampfimg'swarme." 



§ Journ. Amer. Chem. Soc. xxxi. p. 1099 (1909). 

 |j Phil. Mag. xx. p. 665 (1910). 



