584 



SCIENCE PROGRESS 



that viscosity is intimately connected with density, as originally 

 maintained by Laplace and recently supported by Batschinki 

 (Zeitsch. f. Physikal. Chemie. 84, 643, 191 3), Arrhenius finds 

 that regularities become apparent if we have regard not to the 

 viscosity (rf) itself, but to the quotient 17 : \/s, where s is the 

 specific weight of the liquid at its boiling-point. The nature 

 of these regularities, and the extent of their uniformity in the 

 several groups of correlated substances, may be seen from the 

 following excerpts from the lengthy tables of results furnished 

 by the observations of Thorpe and Rodger, as calculated by 

 Arrhenius. The tables are too long to be given in full, but 

 the examples quoted are typical of the whole, which comprises 

 eighty-eight liquids, comprehended under twenty groups of 

 homologues or correlated substances. 



Values of the Viscosity Coefficient 77, the Density s, and of rj : vs at the 



Boiling-point 



Substance. 



Pentane . 



Iso-pentane 



Hexane 



Iso-hexane 



Heptane . 



Iso-heptane 



Octane 



Acetaldehyde 

 Ethyl ether 

 Methyl propyl ether 

 Ethyl propyl ether 

 Dipropyl ether . 

 Methyl isobutyl ether 

 Ethyl isobutyl ether 



Methyl formate . 

 Ethyl formate . 

 Propyl formate . 



Methyl acetate . 

 Ethyl acetate . 

 Propyl acetate . 



Methyl propionate 

 Ethyl propionate 

 Methyl butyrate 

 Methyl isobutyrate 



jj . io" : -v s. 



