Mixtures of Liquids and of Solutions. 



139 



It is therefore necessary to turn to stronger solutions for 

 a comparative test o£ the three formulae corresponding to 

 the three models of a mixture represented at the beginning 

 of this paper. The only available observations are those of 

 Burkhard quoted in Landolt and Bornstein^s Tabellen (2nd 

 edition, p. 294) *. 



Sugar Solution at 20° C. 



P. cent. 



Sugar. 





Specific Viscosity. 









' 





Calculated. 





Weight. 

 



Vol. 

 



p. cent, of 



30% Sol. 



Obs. 

 1-0 









Vis. 



forml. 



p. cent, 

 error. 



Log. 

 forml. 



p. cent, 

 error. 



Mob. 

 forml. 



p. cent., 

 error. 

















5 



3-2 



151 



1-15 



1-31 



+ 14 



118 



+3 



Ml 



-4 



10 



6-5 



30-6 



1-33 



1-63 



23 



1-41 



6 



1-26 



5 



15 



9-9 



46-5 



1-56 



1-96 



26 



168 



8 



1-46 



(> 



20 



13-5 



63-4 



1-89 



2 31 



22 



1 204 



8 



, 1-75 



7 



25 



17-2 



80-8 



2-35 



2-67 



14 



247 



5 



2-20 



6 



30 



21-3 



100 



3-07 















As was found in the case of most of the mixtures of 

 liquids, the linear viscosity law gives much too high, the 

 logarithmic law somewhat too high, and the mobility law 

 somewhat too low values for the viscosity. 



The failure of the three formulae deduced theoretically on 

 the assumption that the constituents of a mixture are dis- 

 tributed as show r n in figs. 1, 2, 3, and 4 respectively, to 

 express the results of observations, leads one to attempt to 

 find an empirical formula capable of so doing. As the 

 deviations from the three formulae are found to be different 

 in different mixtures, it is evident that any such formula will 

 involve an additional constant depending on the particular 

 mixture considered. 



The forms of the above three formulae : — 



1 



= Vi \-v 



Vi 



V2 



* Since this was written the observations of Hosking have been 

 published (Phil. Mag. xlix. p. 274 ; 1900) and are considered pp. 143, 144. 



