THE VISCOSITY OF PURE LIQUIDS 589 



just referred to, in which the errors of observations are small 

 (about 0*2 per cent.), Arrhenius finds that the influence of 

 temperature on viscosity may for non-associated liquids be 

 expressed by 



d\ogy.v\ _K X 

 dt T 2 



Where v is the specific volume and rj the viscosity of the liquid 

 at the absolute temperature T and K x is a constant. K x is 

 nearly proportional to the absolute temperature T 6 of the 

 boiling-point of the liquid, so thati^ : T 6) if common logarithms 

 are used for calculating K x , does not for normal liquids change 

 between greater limits than 1 and 1*2. Exceptions are found 

 in the case of liquids in which the value 



Kl==T dt 



shows no minimum below the boiling-point. For associated 

 liquids the values of K x : T 6 are much higher, viz. between 

 1*25 and 4*32 (trimethyl carbinol). There is also found a 

 close parallelism in these liquids between the values of 

 Ve : </s and K x : T G . In a homologous series K x : T 6 increases 

 with the boiling-point, recalling the analogous behaviour of 

 Trouton's Constant. Hence the analogy in the change with 

 temperature of the vapour pressure and that of the value of the 

 viscosity multiplied by the specific volume of the liquid. 



The following tables contain a summary of the values of 

 io 5 . 777 : Vs = A, and of K x : T 6 = B arranged in order of increase 

 of A for the several groups of liquids upon which the above 

 general deductions are based : 



Normal Liquids 



a. B. 



Unsaturated hydrocarbons 233 1 '002 



Acetaldehyde 249 1*005 



Paraffins 257 1-078 



Aromatic hydrocarbons (4 c C S H 6 ) 267 i'o88 



Ketones 270 1-074 



Mercaptans 275 I'oia 



Iodides 277 1-073 



Acid anhydrides 279 I' 1 53 



Esters 288 1*169 



Monobromides and acetylene dibromide .... 299 1 -079 



