2 AKT. 5. — T. HIRATA I ON THE VISCOSITY 



Believing it to be of some interest to determine whether 

 such regularities exist in other solvents than water, I undertook 

 some experiments on the viscosities of alcoholic solutions. 



The following experiments were made using ethyl alcohol 

 as the solvent, which was obtained by dehydrating commercial 

 " absolute alcohol " with freshly burnt lime ; all the dissolved 

 substances used, were tested for the impurities frequently con- 

 tained in them and freed from these ; their densities, boiling 

 points and, when easily observable, their melting points, were 

 compared with those given for the pure substances and found 

 quite satisfactory. 



The experimental method was as follows : — A glass tube, like 

 an ordinary test tube closed at one end, and furnished with a 

 glass stopper at the other, was taken. The tube was graduated 

 in cubic centimeter from the bottom up to 20 c.c. Into this 

 tube the required volume of the liquid to be dissolved was poured 

 and the solvent alcohol gradually added, with frequent shakings, 

 until it filled 20 c.c. The dissolved substance and the solvent, 

 before mixing, were kept in a thermostat whose temperature was 

 25°C. The solution thus made was kept in the thermostat for 

 a sufficient length of time before it viscosity was measured. 



Solutions containing only one dissolved substance were made 

 as follows, and the measurements made on each : At first, 

 5 c.c. of the substance to be dissolved was taken and diluted 

 to 20 c.c. with the alcohol ; then the half, i. e. 10 c.c, of the 

 solution, was taken and diluted again to 20 c.c. ; in this way, 

 25, 12.5. 6.25, 3.125, 1.5625 and 0.7813 vol. per cent, sohitions 

 were made. 



The viscosimeter used in the experiment was that of Ostwald 

 (Fig. 1) and had the following dimensions : Length of the 



