1907-8.] On the “Negative” Viscosity of Aqueous Solutions. 461 
XXXI. — On the “ Negative ” Viscosity of Aqueous Solutions. By Dr 
W. W. Taylor and T. W. Moore, M.A., B.Sc., Carnegie Research 
Scholar. Communicated by Professor Crum Brown. 
(Read June 1, 1908. MS. received June 8, 1908.) 
The subject of the “ negative ” viscosity of solutions has of late 
attracted considerable attention. Since the publication of the paper by one 
of us with Ranken * in the Transactions of the Royal Society of Edinburgh, 
there have appeared a paper by Jones and Veazey,*j* § and two by Getman.J § 
Since the latter of the papers by Getman contains a comprehensive 
review of the older literature on the subject, it is unnecessary for us to do 
more than indicate those points which are of fundamental importance. 
First noticed by Htibner in 1873, “ negative ” viscosity was observed by 
Sprung in the course of his extensive researches to occur in solutions of 
several potassium and ammonium salts, while corresponding sodium salts 
do not cause it. Later investigations added to the salts which are known 
to give rise to it ; mention may be made of hydrobromic acid, in which it 
occurs at low temperatures but not at higher temperatures, whilst it does 
not occur at all in the case of hydrochloric acid..'||’;i 
Euler’s explanation of the phenomenon, based upon Nernst and Drude’s 
theory of electrostriction, was put forward at a time when no exception 
was known to the rule that “ negative ” viscosity only occurs in aqueous 
solutions of a limited number of electrolytes. It became untenable so soon 
as Wagner and Miihlenbein H found that solutions of certain organic sub- 
stances in organic liquids, e.g., cyanobenzen in alcohol, also possessed 
“ negative ” viscosity. 
Rtidorf** had just previously obtained values for the viscosity of 
carbamide solutions in water at 25° C., which were smaller than the 
viscosity of the solvent, but Fa wsitt,ff working with a very pure sample of 
* Trans. Boy. Soc. Edin., xlv., part ii., p. 397, 1906. 
t Amer. Chem. Journ ., xxxvii. p. 405, 1907. 
J Journal de Chemie Physique, v. p. 344, 1907. 
§ Jour. Amer. Chem. Soc., xxx. p. 721, May 1908. 
|| Taylor and Ranken, Proc. Roy. Soc. Edin., xxv. p. 231, 1904. 
IT Zeit. f. physikal. Chem., xlvi. p. 872, 1903. 
** Zeit.f. physikal. Chem., xliii. p. 257, 1903. 
ft Proc. Boy. Soc. Edin., xxv. p. 52, 1904. 
