334 C. E. Linebarger — Viscosity of Mixtures of Liquids, 



a degree ; it bad been sbortl j before tested by the '' Ph jsika- 

 liscbe Reicbsanstalt," and bad been found to be without appre- 

 ciable error in the neighborhood of 25°*0. 



In order to convert the relative coefficients of viscosity, 

 obtained directly from the experimental data furnished by the 

 apparatus, into coefficients of viscosity expressed in dynes per 

 square centimeter, the former vrere multiplied by the factor 

 0*00895 ; this number being the average of the results obtained 

 for v^ater at 25°*0 by Poiseuille, Sprung, Slatte, and Thorpe 

 and Kodger.* 



/ 

 III. Experimental Results. 



In the following tables are recorded the experimental results 

 obtained. In the first two columns are given the percentage 

 composition, in the second two the molecular percentage com- 

 position, of the mixtures of liquids investigated. These mix- 

 tures were prepared by weighing out to less than a milligram 

 the liquids in tared flasks or bottles fitted with the best corks. 

 The fifth column contains the specific gravities at 25°*0 referred 

 to water at the same temperature. In the sixth column are 

 placed the viscosities of the mixtures as calculated from those 

 of their component liquids by the rule of mixtures, while in 

 the seventh are set the viscosities as actually determined. The 

 eighth column finally shows the differences between the calcu- 

 lated and observed viscosities ; a plus sign indicates that the 

 calculated viscosity is greater than that determined ; a minus 

 sign, the contrary. 



Table I, 



Viscosity of Mixtures of Benzene {a 



.11) and Ethyl Ether (b.) 









Temperature — 25°-0 





Molecular 









Percentage 



percentage 



Specific 



Calculated 



Observed 



composition. 



composition. 



gravity. 



viscosity. 



viscosity. Dtff. 



CeHe C4HX0O 



CeHe C4H10O 









0-000 100-000 



0-000 100-000 



0-70942 





000230 



28 576 '71-424 



27-502 72-498 



0-75369 



0-00335 



000282 +0-00052 



56-924 43076 



55-627 44-373 



0-79972 



000440 



0-00362 +0-00078 



75-691 24 309 



74-709 25-291 



0-83179 



000509 



000438 +0-00071 



100-000 0-000 



100-000 0-000 



0-08390 





000599 



{a. II.) About five pounds of " chemically pure " benzene 

 were treated repeatedly with sulphuric acid to remove last 

 traces of thiophene, and fractionally crystallized many times. 

 It was then distilled over some scraps of sodium, the whole of 

 it boiling at 80°*12 (corr.) under a pressure of 757*3°'°^ of mer- 



* See Thorpe and Rodger " On the Relations between the Viscosity (Internal 

 Friction) of Liquids and Their Chemical Nature " (Bakerian Lecture), Phil. 

 Trans., 449, 1894. 



